It puts them in a very precarious position. They know when they take the pledge that it's not in the public's interest.

It is certainly a precarious position for the program.

'Our federal caucus is in a precarious position,

These are the kinds of issues that whip up people in primary elections. The turnout is going to be really low, so I think these candidates are looking for something that whips up the faithful and increases the turnout for them.

It gives you access to Republican interest-group money that you don't have if you don't take the pledge.

The advantage to party leaders is it gives them a way to enforce discipline in the House and the Senate that leaders in the past didn't have.