In early September, President Barack Obama announced that he would seek congressional approval before taking military action in Syria. Evidence was mounting that Bashar al-Assad had used chemical weapons against rebels in his fight for control of Syria. Obama and his predecessors in the White House had authorized military strikes before without asking for Congress’ input, but this time the situation was different. Americans were tired of war. To move forward, Obama would need some people on his side. The vote never made it to the floor, but even if it had, any action in Syria would almost certainly not be called a “war” in the traditional sense.

“Under the Constitution, the responsibility to declare war lies with Congress,” said Speaker of the House John Boehner in a statement. “We are glad the president is seeking authorization for any military action in Syria in response to serious, substantive questions being raised.”

The ancient Greeks defined war as an armed conflict between states. When one country had a disagreement with another that couldn’t be solved through diplomacy, they would take up weapons and go to war. Over time, that definition changed. Political philosopher Carl von Clausewitz wrote after the Napoleonic Wars war is “the continuation of policy by other means.”

The 20th century was a period marked by some of the most widespread warfare in human history. According to The New York Times, the Correlates of War project, which gathers scientific data on war, defines it as “a conflict in which there are 1,000 battlefield deaths.” Even by this measure, war is still loosely defined by the international community.

Many recent conflicts would not qualify under this definition. With the U.S. shifting its focus to surgical strikes and Special Forces missions designed to take out a handful of targets, is a conflict where only one or two people are killed count as war?

The U.S. has only officially declared war 11 times in its history; the last time was World War II. Every conflict since then, from Korea to Afghanistan, has been authorized under a different name. Congress attempted to prevent the president from circumventing its Constitutional power to declare war with the War Powers Resolution of 1973, which imposed a 60-day limit on military engagements without Congressional approval.

In practice though, the War Powers Act is hard to enforce. While Congress has the option to cut off funding to the military, it rarely does so, reports NPR. The White House often argues that the law infringes on the president’s role as commander-in-chief of the armed forces.

“Again and again, you try to find some credible way to at least request that the Executive Branch honors the War Powers Act,” Anthony Cordesman, a national security analyst at the Center for Strategic and International Studies, told NPR. “Again and again, you back away and weaken Congress.”

Today’s wars are less and less like the wars of the 20th century. Conventional war is increasingly taking a backseat to drone strikes and Special Forces raids. States are no longer the principal actors in the modern theater of war, but rather individuals and terrorist groups engaging in violence on a smaller scale than the world wars of the last century.

“Among the details that the United States will not reveal are how many people it has killed, including civilians,” reports Foreign Policy in an article investigating drone strikes in Yemen. “It also refuses to detail the full legal framework under which it carries out the killings, or what actions it takes, if any, when attacks go awry.”

A diplomatic solution came before Congress could vote on the possibility of launching an armed intervention in Syria’s civil war. The U.S. military is winding down from the hot wars in Iraq and Afghanistan. The strategy of sending small, specialized units to capture or kill terrorists is likely to replace full-scale war. War is evolving — the legal definition of war is likely to change with it.