I mentioned earlier today all of the poison pills that House Republicans want to tuck into their payroll tax/unemployment insurance legislation. Their plan is to pass something with these right-wing riders attached to attract conservative votes, preferably next Wednesday, and then leave town for the year. This has been thwarted on two fronts today.

First, Harry Reid said that the Senate will stay in session until payroll tax legislation passes both houses and gets signed by the President. They will not get jammed by the House, according to Reid, because they will just wait it out and force pressure on the House to return to work.

Of slightly more importance, President Obama vowed to reject any legislation on the payroll tax that includes unrelated poison pills, though he did not go so far as to say the word “veto.” And he mentioned the Keystone XL pipeline by name, in a press conference with Prime Minister Stephen Harper of Canada, who has more than a passing interest in the policy. “Any effort to try to tie Keystone to the payroll tax cut I will reject,” Obama said. “If the payroll tax cut is attached to a whole bunch of extraneous issues, then it’s not something that I’m going to accept.”

This probably won’t stop the House from passing their preferred version of the bill. But it does mean that the scope of options have been narrowed, either to compromise legislation without unrelated riders, or no deal and a lot of finger-pointing.

UPDATE: More context on the President’s statement:

“If the payroll tax cut is attached to a whole bunch of extraneous issues, not related to making sure that the American people’s taxes don’t go up on January 1, then it’s not something that I’m going to accept. I don’t expect to have to veto it because I expect they’re going to have enough sense over on Capitol Hill to do the people’s business and not try to load it up with a bunch of politics,” Obama said.

So a “I’ll veto but I won’t have to” threat.