"I expect my Senate colleagues to be up for the battle," he said.
The prospect is for a 10-day period of intense uncertainty, with Boehner pledging to avoid a shutdown yet also hoping to come away with a bite out of the health care law, even if less than complete defunding.
Congressional aides pointed out during the day, for example, that if the Senate rewrites the House-passed bill to leave the health care law in place, Boehner and the rest of the House leadership could still seek further changes before passing it a second time.
For their part, the White House and majority Democrats in the Senate will be trying to protect the health care law that stands as Obama's signature domestic accomplishment — without complicating the re-election chances of senators on the 2014 ballot in swing states.
The White House intruded briefly on the Republican feud, pledging that Obama would veto any legislation that blocks the health care law from taking full effect. The defunding drive "advances a narrow ideological agenda that threatens our economy and the interests of the middle class" and would deny "millions of hard-working, middle-class families the security of affordable health coverage," it said.
The effort seeking virtual repeal of the law as part of a government funding bill gained powerful momentum over the summer when the Senate Conservatives Fund, Heritage Action and other groups with tea party ties launched a nationwide campaign.
Cruz and Lee played prominent roles, each appearing in television ads aimed at pressuring Republican lawmakers not to yield. "Republicans in Congress can stop Obamacare if they simply refuse to fund it," Lee says in one SCF-funded commercial.
On the other hand, the U.S. Chamber of Commerce has urged Republicans to fund the government and prevent a default, then double back and try and work out changes to the health care law later.