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One of the reasons that members of Congress like to work with the executive branch is that the executive branch has much more in the way of technical resources than the legislative branch. An individual senator does not have the manpower needed to reform the tax code. The Treasury Department does. Access to that sort of expertise and staff help can be crucial when Congress is working on a complex legislative proposal, which any comprehensive deficit-reduction bill would doubtless be. But that support can be provided quietly, and I rather doubt that the White House would withhold it if a group of senators came knocking. What would they say? “Sorry, Senator McCaskill, but we’d prefer you to trash us in the press instead?”

What the Gang of 64 asked from the president, however, was “strong signals” of support. That is to say, they wanted something more public. But that might not serve their purposes as well as they think. There’s a common assumption in Washington that legislation passes because the president pushes it. That actually gets the causality reversed: The president often chooses to push legislation that can pass, which is why the Obama administration fought for health-care reform but not cap-and-trade. But people get used to that connection: What passes is what the president pushes.

That impression might not just be wrong, however. It might be backward. As the political scientist Frances Lee has found, when the president takes a stand on an issue, that tends to polarize it — which is to say, the very act of the president identifying himself with a particular effort makes it more difficult for Republicans to support it. To quote a previous post I wrote summarizing her research, Lee looked at “ ‘nonideological’ issues — that is to say, issues where the two sides didn't have clear positions. In the Senate, only 39 percent of those issues ended in party-line votes. But if the president took a position on the issue, that jumped to 56 percent. In other words, if the president proposed the ‘More Puppies Act,’ the minority is likely to suddenly discover it holds fervently pro-cat beliefs.”

A good example of this was the tax deal, where the GOP was able to agree to policies, like the payroll-tax cut, that they would have aggressively opposed if they’d been part of the Democrats’ 2010 campaign message.

You can see why this puts modern presidents in a pickle: The public expects them to take the lead on everything, but by taking the lead, they make it harder for the minority to follow. The president is in the odd position of getting more done when he appears to be doing less. But senators have not only seen this dynamic in action, they’ve participated in it. So they should be a bit less excited about having the president charge into the middle of delicate, bipartisan negotiations. And yet, as far as I can tell, they almost always want the president out in front. I assume that’s out of a natural desire to see the president use his megaphone to move their issues to the front of the agenda, but the way in which they get moved to the front of the agenda — a presidential announcement that kicks off a partisan conflicts that the media then covers — is not necessarily helpful.