That is, assuming they want to. Here’s a piece of mine about this in Mother Jones:
What would a serious congressional strategy to block a war with Iran look like? Constitutional scholars and congressional staff agree there’s no one magic answer. The alarming truth is that 220 years after the adoption of the Constitution, there are few settled answers about what legal powers the executive branch possesses to start a war. But there are several steps Congress could take to make a war with Iran politically very difficult for the White House…
The limiting factor on a determined president is not whether an attack is “legal.” Rather, it is how high a political cost he’s willing to pay.
I found it hard to get my mind around this, but it’s true. If the executive branch is determined to do something, it’s extremely difficult for the legislative branch to stop it merely with laws.
For instance, take the spying program about which James Comey just testified. Congress has written clear laws about what domestic surveillance the executive branch can and cannot carry out. And it’s the Justice Department’s job to interpret such laws for the executive branch. But when the Justice Department told the White House that what they were doing was illegal, the White House didn’t say, “Oh! Well, we’ll definitely stop then.” Instead, they decided to keep on doing it. They only modified the program when all the top Justice Department officials threatened to resign.
In other words, it wasn’t the law that stopped them by itself, but the political damage they would have suffered from all the resignations. If they’d been willing to suffer that damage, the White House could have let everyone quit and then hire replacements who’d come up with some theory about why the spying program was legal.
So Congress should pass laws forbidding Bush from attacking Iran—but that by itself isn’t enough. They need to use all the tools they have to create a climate in which the political cost to the Bush administration of starting a war would be excruciatingly high. Those tools are what the article is about.
AND: Speaking of laws, Congress is voting today on the DeFazio-Paul-Hinchey-Lee amendment to the defense authorization bill. This amendment tells Bush he can’t attack Iran without congressional permission. If you think war with Iran is a bad idea, call the Capitol Hill switchboard at 202 224-3121 and ask your representative to support it.
Nope, the vote happened last night, and the amendment failed 136-288. Never trust the word of twelve year-old Capitol Hill staffers. Interestingly, Pelosi isn’t listed there at all.
MORE: Emailers tell me the Speaker of the House generally doesn’t participate in votes like this. Don’t ask me why.