Kind of too little, too late from John Conyers:Join Me in Calling on President Bush to Respect Congress' Exclusive Power to Declare WarDear Democratic Colleague:As we mark five years of war in Iraq, I have become increasingly concerned that the President may possibly take unilateral, preemptive military action against Iran. During the last seven years, the Bush Administration has exercised unprecedented assertions of Executive Branch power and shown an unparalleled aversion to the checks and balances put in place by the Constitution's framers. The letter that follows asks President Bush to seek congressional authorization before launching any possible military strike against Iran and affirms Senator Biden's statement last year that impeachment proceedings should be considered if the President fails to do so.Never mind the fact that the dead-ender Senate Republican caucus wouldn't convict. A military strike on Iran would be likely to happen this summer at the earliest, probably not until October (surprise!). Then there are the hearings, and the vote in the House Judiciary Committee, and the vote in the full House, and the trial in the Senate, and the vote. Let's say for the sake of argument that every Republican in the Senate gets religion and decides to convict to sever all ties with this guy for good.What does that mean, he gets to leave early and skip a weekend? The guy's got senioritis as it is.The leverage of impeachment is over. That moment has passed.