As the U.S. Congress returns from its August recess and begins deliberations on the use of force in the Syrian conflict, it’s a good time for a look back at how America has gone to war in the past.

Under the 1973 War Powers Resolution, presidents must ask Congress for approval before initiating military force lasting more than 60 days. That gives Congress a say in the big conflicts, but it also allows presidents considerable leeway in smaller interventions.

Ronald Reagan took advantage of the rule to invade Grenada in 1983, and launch airstrikes against Libya in 1986. George H.W. Bush used it to send troops into Panama in 1989, and Somalia in 1992. Bill Clinton used it to intervene in Haiti and Bosnia in 1994, as well as order cruise missile attacks on Iraq, Afghanistan, Sudan, and Kosovo throughout the 1990s.

Even Nobel Peace Prize winner Barack Obama used the rule to allow U.S. forces in Libya in 2011. American troops actually stayed in combat more than 60 days during the Libyan mission; Obama argued that they were technically under NATO control and therefore didn’t fall under the War Powers Resolution. The House of Representatives disagreed, formally rebuking the president.

Now, after more than a decade of war in both Afghanistan and Iraq—not to mention a war footing around the world as a result of the September 11, 2001 terror attacks—much of the U.S. population finds itself uneasy about another military intervention.

And, in light of alleged chemical weapons abuses by Bashar al-Assad’s government, the president finds himself going to congress to ask for approval for the use of force in Syria. 

Constitutionally, does he need it? No.

Politically? Yes.

Congressional approval will not only lend legitimacy to the mission, but it will help to spread the blame around should things go sour.

For when it comes to American military conflicts with congressional approval, the track record hasn’t always been wonderful. All one needs to do to see it is peruse the report Declarations of War and Authorizations for the Use of Military Force: Historical Background and Legal Implications by Jennifer K. Elsea and Matthew C. Weed, published this year by the Congressional Research Service.

Looking over Elsea’s and Weed’s chronology of key congressional authorizations for the use of force during the history of the United States, one can plainly see that the incidents since the 1950s have had long-ranging, and often unexpected, consequences:

January 29, 1955—against China, in an American military commitment to defend Formosa (now Taiwan).

March 9, 1957—for “peace and security of the nations in the general area of the Middle East”.

August 10, 1964—against Communist insurgencies in southeast Asia (also known as the Gulf of Tonkin resolution, this lead to buildup and use of U.S. forces in Vietnam).

October 12, 1983—for peacekeeping in Lebanon.

January 12, 1991—against Iraq, following that country’s invasion of Kuwait.

September 18, 2001—against terrorists, following the September 11 attacks (this lead to the invasion and subsequent occupation of Afghanistan).

October 16, 2002—against Iraq.

The Korean War (1950-1953) is one notable exception. As intervention was a United Nations mandate, President Harry Truman was able to commit a massive amount of American troops (almost 90 percent of the nearly 350,000 U.N. troops) without congressional approval or a formal declaration of war.

Elsea’s and Weed’s report also makes another thing clear—while Congress has formally declared war only 11 times, it’s historically worked out better for the United States than an authorization of force:

June18, 1812—against Great Britain (essentially a draw).

May 13, 1846—against Mexico (the U.S. came away with California, New Mexico, Arizona, Nevada, Utah, and parts of Wyoming, Colorado, and Texas).

April 25, 1898—against Spain (the U.S. occupied Cuba, Puerto Rico, Guam, and the Philippines, as well as emerging as a geopolitical power).

April 6, 1917—against the German Empire (huge economic benefits as well as European influence).

December 7, 1917—against the Austro-Hungarian Empire (allied with Germany).

December 8, 1941—against the Empire of Japan (economic benefits as well as Asian influence).

December 11, 1941—against Germany (economic and technological benefits, as well as European influence and a continental foothold in the upcoming Cold War).

December 11, 1941—against Italy (allied with Germany).

June 5, 1942—against Bulgaria (allied with Germany).

June 5, 1942—against Hungary (allied with Germany).

June 5, 1942—against Romania (allied with Germany).

So why have conflicts with a declaration of war worked out better for the United States than those with a simple congressional approval?

The discrepancy may be a matter of personality. Where declarations of war have tended to revolve around territorial aims or threats from other nations, military intervention seeking congressional approval usually hinges on the will of one person—the president—and his ability to influence, cajole, and reward the members of Congress.

Of course, in the end it’s all just semantics. A declaration of war, presidential fiat, or congressional authorization likely all amount to the same thing if you’re the one shooting, or being shot at.