Following 10 hours of debate, the British Parliament voted late Wednesday evening to participate in the bombing campaign in Syria against the Islamic State. Reuters reports on the vote here, and The Guardian provided live coverage, including vote breakdowns, for those following the nitty gritty of British politics. Parliament had voted last year to participate in strikes in Iraq, but not Syria, so Wednesday’s vote represents an expansion of Britain’s air war against ISIS.
The most interesting aspect of this vote is not the outcome — no one really thinks British participation will suddenly turn the tide of the fight against ISIS — but rather the fact that the vote happened at all. Under the U.K.’s (unwritten) constitution, the “royal prerogative” reserves power over the armed forces and foreign affairs, including the commander-in-chief powers and the power to declare and end wars, to the monarch. [As background, this report provides an interesting history of the common-law background of this power.] This power is now exercised by the Prime Minister, on the monarch’s behalf. This means that –at least in theory—the British Prime Minister can deploy troops and engage in the use force without Parliament’s approval. In fact, Parliament was not involved in the decisions to fight World War I, World War II, the Korean War, or the 1991 Gulf War. The Prime Minister also did not seek approval for engagements in the Suez crisis, the Falklands crisis, or even the 2001 Afghan war.
However, this understanding has evolved over the past decade or so, beginning with the 2003 vote approving British participation in the Iraq War. There, Tony Blair took the vote to Parliament out of apparent political necessity, rather than to fulfil a legal obligation. The practice of seeking Parliamentary approval has, nonetheless, continued since then. The British prime minister sought Parliamentary approval for military involvement in Libya—though that debate took place after military action had already begun—as well as in Syria, following Assad’s use of chemical weapons. In the Syrian case, the Prime Minister lost the vote and therefore decided not to send troops). Parliamentary approval was sought—and given—to fight ISIS in Iraq and now in Syria. Thus far, the government has not moved to legally codify the consultation requirement, but the practice is reflected in Prime Minister David Cameron’s Cabinet Manual and the practice has been adopted in four instances.
The British trend stands in contrast to a move towards congressional disengagement from use of force debates in the United States. The U.S. Constitution requires, at least in some circumstances, congressional approval for the use of force. And Congress has attempted to further develop the constitutional requirement by imposing statutory obligations through the War Powers Resolution. Yet, Congress has stood quietly by after passing the 2001 and 2002 AUMFs for Afghanistan and Iraq. Unlike the UK Parliament, Congress has not authorized—and some cases not even voted on—the use of force against Qaddafi in Libya, Assad in Syria, or ISIS in either Iraq or Syria. To the contrary, even when the President has asked Congress to act, it has declined.
The U.S. Congress has found other ways to voice its opinions — President Obama was unlikely to have obtained congressional authorization for the use of force against the Assad regime after it employed chemical weapons in 2013 and, ultimately, he did not intervene militarily at that time. But while British Parliament has authorized the use of force four times since 2003, Congress has not done so once since 2002, even though the United States and the United Kingdom are engaged in many of the same battles around the world. To be sure, President Obama has interpreted the 2001 and 2002 AUMFs to authorize action against ISIS in Iraq and Syria. But this interpretation is contested, and moreover, it cannot explan why the legislative votes in the U.S. and U.K. reached different outcomes. Overall, as the United Kingdom moves toward a regime of legislative approval for war, the United States appears to be turning away from the same.