Thomas's Foot Still in His Mouth

Here is Ways and Means Chairman, William Thomas (R-CA), trying to amend last week's statement about Bush's Social Security plan being a "dead horse":

I didn't say it was dead on arrival," he said. "What I said was, I hope we didn't have our friends on the other side of the aisle attacking the president's proposal once it's introduced. Because, once it's introduced, it becomes part of the legislative process. Suggest changes or suggest substitutions, but don't continue the arguments against the president's plan, because it's now part of the legislative process. That would be beating a dead horse."

What? Once the President's plan has been introduced you can only suggest changes, you can't "attack it" or oppose the whole thing? Students of Congress must be racking their brains trying to figure this enunciation of legislative procedure out.