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Legally Speaking, the NATO Treaty Does Not Require the U.S. to “Automatically” Use Force to Defend Allies

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Legally Speaking, the NATO Treaty Does Not Require the U.S. to “Automatically” Use Force to Defend Allies

Charlie Dunlap, J.D

Cross-post with Lawfire

The New York Times is carrying a story (“Donald Trump Sets Conditions for Defending NATO Allies Against Attack“) reporting that the Republican presidential candidate “explicitly raised new questions about his commitment to automatically defend NATO allies if they are attacked.”  Mr. Trump, the Times says, would “first look at their contributions to the alliance” before deciding upon a response.

Without commenting on the wisdom of this position, allow me to answer this question: as a matter of law, does the NATO treaty “automatically” require the U.S. use force to defend a NATO ally?  The short answer is “no”.

Here’s what Article 5 to the NATO treaty provides:

The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognized by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.

The crucial point is that the response to an “armed attack” that a NATO member owes to a NATO ally is simply whatever “it deems necessary.”  NATO itself provides an explanation that illustrates that the U.S. has always resisted the notion of an “automatic” obligation:

At the drafting of Article 5 in the late 1940s, there was consensus on the principle of mutual assistance, but fundamental disagreement on the modalities of implementing this commitment.  The European participants wanted to ensure that the United States would automatically come to their assistance should one of the signatories come under attack; the United States did not want to make such a pledge and obtained that this be reflected in the wording of Article 5. (Italics added.)

Importantly, Article 5 should not be read in isolation from Article 11 which states that “the Treaty shall be ratified and its provisions carried out by the Parties in accordance with their respective constitutional processes.  (Italics added.)  Following the Paris terrorist attacks last November, Hofstra’s Professor Julian Ku referenced Article 11’s acknowledgement of the need for countries to adhere to their “respective constitutional processes” and observed this about the relationship of U.S. domestic law to the NATO Treaty:

If you are someone who believes that Congress must authorize the use of force by the President in most cases, than this language would mean that the President has to go back to Congress.  This might actually happen.  Republican presidential candidate Jeb Bush actually called for a “declaration of war on ISiS today.  Of course, if you believe (as I do) that the President has independent constitutional authority to use military force without Congress in most circumstances, than all Article XI does not limit the President much.

The key is that the NATO Treaty neither obviates the need to find domestic U.S. legal authority to use force, nor forecloses a decision not to use force at all.

Significantly, Ku has also pointed out elsewhere that most U.S. treaty obligations are similar, that is, they do not, as a matter of law, automatically act as some sort of pre-authorization to use force but rather must also find U.S. domestic law support either in a declaration of war or other statutory authorization, or within the President’s authority under Article II of the Constitution.  In discussing (last January) US obligations towards Taiwan Ku said (and I agree) that:

Ultimately, the core of any security guarantee is not legal obligation, but political will.  Legally speaking, Taiwan lacks an ironclad U.S. security guarantee against an attack by China, but this is true for just about everyone else as well including NATO.  Whether the U.S. will come to the defense of Taiwan, or any other country, is largely contingent on questions of diplomacy, military facts, and political will.  (Italics added.)

Interestingly, in March of last year The Economist dismissed the argument made by some Baltic states who feel threatened by Russia “that an attack on them would mean an all-out East-West confrontation thanks to Article 5 [of the NATO Treaty]” by concluding that “Article 5 does not specify such a response.”  It said that “[t]he decision to act, or not, would be made not at NATO HQ in Brussels, but in Washington, DC”, adding that as “many eastern NATO members worry, it is hard to imagine an American president risking nuclear war to defend a tiny country half a world away.”

According to the Times, Mr. Trump’s position is based on his concerns about NATO members “taking advantage of what he called an era of American largess that was no longer affordable.”

The U.S. is, by far, the largest contributor to NATO.  Indeed, while U.S. defense spending amounts to about 3.6% of GDP, only four other NATO members are meeting NATO’s own guideline of spending 2% of GDP on defense.  In 2011 former Secretary of Defense Robert Gates warned NATO that:

The blunt reality is that there will be dwindling appetite and patience in the U.S. Congress — and in the American body politic writ large — to expend increasingly precious funds on behalf of nations that are apparently unwilling to devote the necessary resources or make the necessary changes to be serious and capable partners in their own defense.

Similarly, last April President Obama complained about “free riders,” that is, nations who don’t “carry their weight” in terms of acquiring and maintaining defense capability but who nevertheless expect U.S. security backing.  This wasn’t a specific reference to NATO, but would seem to include its members among other allies.

Be that as it may, the U.S. has more legal flexibility as to the use of force than many might assume defense agreements like that of NATO would allow.

Just for the record, I am a registered independent, and as a retired military officer I do not publicly support any candidate.

About the Author(s)

Charles J. Dunlap Jr., the former deputy judge advocate general of the United States Air Force, joined the Duke Law faculty in July 2010 where he is a professor of the practice of law and Executive Director of the Center on Law, Ethics and National Security. His teaching and scholarly writing focus on national security, international law, civil-military relations, cyberwar, airpower, counter-insurgency, military justice, and ethical issues related to the practice of national security law.

Dunlap retired from the Air Force in June 2010, having attained the rank of major general during a 34-year career in the Judge Advocate General Corps. In his capacity as deputy judge advocate general from May 2006 to March 2010, he assisted the judge advocate general in the professional supervision of more than 2,200 judge advocates, 350 civilian lawyers, 1,400 enlisted paralegals, and 500 civilians around the world. In addition to overseeing an array of military justice, operational, international, and civil law functions, he provided legal advice to the Air Staff and commanders at all levels.


Outlaw 09

Fri, 07/22/2016 - 2:21pm

In reply to by cammo99


Do you honestly believe what you have just written.......if you do then you truly do not understand NATO nor the role of the US inside NATO here in Europe for over 60 odd years.

It is great to rant and point fingers but I will as one who has spent a large part of my life time here in Europe defending you and others since really do not know about which you speak.

If you truly understood Syria then again you would not be saying what you are saying but hey everyone has an opinion...but not many fully see and understand what they are seeing...

Follow the Syrian thread and then you might learn something that could in fact change a number things you state.

JUST a side comment....basically the US has and did pull out of NATO/Europe stating on 9/11 and basically used Europe as a resupply and support center for Iraq, AFG, Libya, and now Syria.

Since 9/11 the US pulled virtually all combat troops out of Europe and NATO and basically left only combat support and logistic troops behind....DoD left only the 173rd Airborne, 2ACR, and 12th CAB...AND surprise surprise the 12th CAB was to be actually pulled out in 2013 but due to Russian aggression they decided to leave it in NATO.

So to argue the great and super strong US Army was spending the so called 2% per year in NATO and fully supporting fully and bluntly said.......stupid. BTW this constant drawdown of US Forces out of Europe started immediately after the Wall fell....

Check just how many USAF bases were also closed down and withdrawn...the 6th Fleet pulled out their attack carrier group out of Naples and regrouped at Rota AND for the first time in years an attack carrier group shows up in the exactly where was that massive amount of money being spent on NATO.....????

WHY...what was left in Europe for US Forces could not have stopped a runaway pigeon flying on one wing and carrying a suitcase.....

So when one talks about NATO, EU, refugees, one needs to be very very very very very well informed.....


Fri, 07/22/2016 - 10:29am

The fact is Trump is getting hit hard because the BLM pro-Islamic organ of the DNC aka NY Times propaganda rag for the Obama admin, have a fear that Trump will limit the over flow of refugees swamping Europe and creating Shariah enclaves in Europe at great expense to the EU. So much so France now deploys 1/3rd of its military to defend Jewish civilian and religious places from attacks. Another 1 to 2 million "refugees" wait in camps on the French coast hoping to jump the channel, although England declared its stepping out of the EU was not a consideration of more mass migrations. The DNC would gladly act as an over flow refugee site for a class of non-citizens who resist every attempt to introduce them to democratic and pluralistic institutions.
Secondly, Trump is merely acting on the fact the USA pays the lion's share and has paid a lion's share of defense on NATO.
Not to downplay the liberty aspiring Balkan States that feel most threatened by Trump's statements.
France now has an annual national debt that nearly equals its GDP. Germany is still growing its GDP but not because of the influx of refugees, it has progressive production, tariffs and other factors but is still struggling with "rape"Ugees. In fact it has begun a no means no policy.
Denmark and Sweden suffer the same problem of cheapening modern and progressive forward looking pluralistic institutions with 7th Century looking Muslims who in 25% of all of England's male Muslim population believe the infidels should subsidize them as a matter of shariah and 50% of the Male Islamic population is out of work and not looking for jobs.
Like BLM they are supremacists, which has little or nothing to do with poverty levels, but is more inclined by ideology and religious and racial bigotry resistant to "change".
The EU is in such turmoil economically it could leave the USA to pay the disproportionate share of defense and what's the return when 2/3rds of your Army is deployed protecting you from terrorists?

Outlaw 09

Fri, 07/22/2016 - 10:24am

In reply to by Outlaw 09 needs to be very very cautious about that so called 2% spending requirement.....that Trump and the author talks about.

Since 9/11 the US has broken their own 2% spending requirement by say a factor of 5000%...vs the rest of NATO.

BUT was that 2% spent in the actual defense of NATO...count the USDs it all went to Iraq and AFG by the TILLIONS while at the same the US military continued to draw out and move out of Europe even in the face of NATO complaints that some of the units should remain....

WHICH we now see are being sent back so will that cost of a bad strategic military decision be added to the US 2%....????

Right now the Russian mercenaries in eastern have MORE tanks that the total number of tanks in both the German and UK armies...and let's not even begin to count any US tanks that largely do not exist in NATO....

THAT 2% debate has always been a smokescreen for other debates inside NATO....

Outlaw 09

Fri, 07/22/2016 - 10:10am

This in interesting in that it proves that yes Trump is in his own "alerted state of reality" or what we call in eastern Ukraine and Syria "vodka moment".....can be wrong.

Nothing about the author's "legal definition moment"..but check history....

If one really checks the use by NATO of Article 5 in the last 60 odd has only been invoked ONCE in those 60 odd years...IN THE DEFENCE of the US immediately after 9/11......SUPPORTED by all 27 members.

So where was Trump or the author??

Also while both Trump and Gingrich seem to want to beat up on Estonia...per population Estonia has suffered the highest personnel loses in their NATO contribution to AFG...AGAIN which somehow both totally overlooked.

WHEN a Presidential candidate gets their facts so convoluted and I hear nothing from their supporters that even questions his ability to be the National Command Authority then we have a serious problem in the US????

WHILE it is great to beat up on NATO for politics...REMEMBER not even the UK is at 2% spending and with Brexit they will never be at 2%.

Also for the entire length of the entire Cold War Germany bore the envious role of paying the US stationing costs for over 500,000 troops for years...

They paid for the bases, they paid for their upkeep, they paid largely for the salaries of those base employees....yes it flowed from the US but at the end of the year Germany paid up. THAT is why when those bases are closed down by the UK, France, Dutch, Canadian or the US all facilities and property reverts directly to the German government.

All those "maneuver damages" over the years with every major NATO Reforger exercise held in Germany....initially paid by the US BUT then at the end of the year Germany paid up......ALL that US military housing...built and maintained at German cost....all those US air bases the same exact thing.

CURRENT Example: the US Army is building a completely new military hospital to replace a very old Landstuhl out of the 50s....the German government is providing the land and building at their cost the entire critical infrastructure to support it including all roads AT their cost even in the face of local voter resistance as they view the need for new German housing to be a higher value than a US military hospital.....

SO while it good to beat up on NATO one must be a little be more cautious in "accussing" others of not paying up....... small overlooked point by the author and Trump is that ...during Desert Storm all the 120mm tank ammo needed for the US tank units in KSA was shipped out of German munition depots as the US Army did not have full stocks in Germany...they only had a 30 day supply and needed a 90 day supply....which then came from a NATO member.

ALL those rail shipments of US equipment to the ME were carried on NATO military rail equipment mainly German NOT US.......

So while the story sounds great...we truly do need to get back to reality....and get there in a hurry....

While some NATO members do not spend the 2% they tend to make up for it in other ways that we never seem to be able to "hear about" in the populist chatter these days....


Thu, 07/21/2016 - 7:34pm

So, what you are saying is that Article 5 is like having a Red Line, that you have announced to everyone in the world is a Red Line, but then you aren't required to do anything about it if it is crossed. Where have I heard that before ...

I admittedly am a layperson. But then what deterrent value does NATO have? I thought that the value of such a structure as NATO was that it removes uncertainty which is the bane of strategic thinking. "If we do A they will definitely do B, and if I don't do A, they will definitely not do B; I don't want them to do B, so I won't do A" where B is explicit and the probability p is exactly 1, is the crux of strategic deterrence an is to perfectly channel someone like Thomas Schelling in Arms and Influence or The Strategy of Conflict. The whole of our nuclear strategy can be attributed to this model.

But if B is vague, reversible, or evitable, isn't the model's efficacy as a deterrent destroyed?