How to Legitimize Intervention in Syria British Prime Minister David Cameron has summoned Parliament back from summer holiday so lawmakers can discuss - and vote on - a response to the chemical attack in Syria. American lawmakers are also on recess, until next week, but it's doubtful that they will follow Britain's lead in returning to Washington early to take up the question of intervention. In recent years, Congress, especially the Republican-led House of Representatives, has proven so dysfunctional and riven by partisanship that it has done little legislating on even the most important issues. While President Obama can't expect much from Congress, he should still, at a minimum, secure backing from legislative leaders for military action. News reports say administration officials have begun briefing the leaders of key House and Senate committees on their plans. Some lawmakers, including Democratic Rep. Adam Schiff of California, a member of the House Permanent Select Committee on Intelligence, and Republican Sen. Bob Corker of Tennessee, a member of the Senate Foreign Relations Committee, have individually endorsed an American response. Of course it would be more consequential if all the top lawmakers issued a joint statement supporting whatever action Mr. Obama decides to take. Also on our wish list: It would be better if the United States, Britain and their partners sought authorization, and legal justification, from the United Nations Security Council for any military action. Although Russia and China have repeatedly thwarted past anti-Assad moves, there is value in forcing them to choose whether to continue standing with a leader who is now accused of gassing innocent civilians, or with the rest of the international community. Absent a security council vote, it is important that Mr. Obama and his partners - France and Turkey have also indicated that they will back the use of force - rally as much international institutional support as possible, from NATO, the Arab League and the European Union. On Tuesday, the Arab League, after an emergency meeting, issued a statement blaming Mr. Assad for the chemical attack. But the league made no mention of military action, so the statement can hardly be considered an endorsement for an American offensive, nor a commitment that league members would join in the operation. Whatever Mr. Obama decides to do on Syria, he needs to clearly explain to the American people the legal basis of any operation, his strategic and tactical intent and how he plans to keep the United States from getting mired in another Middle East war.