How far will Republicans go to defund Obamacare?

That’s the key question in Washington this week. The House passed a budget bill last Friday that would fund the government through Dec. 15. The bill excludes spending for the Affordable Care Act, the federal health care legislation that became law three years ago, setting the stage for a major bipartisan fight in the Senate this week.

Related: DC Budget Showdown: Ugly, Familiar, Avoidable

If Congress and President Obama cannot agree on a continuing budget resolution before Oct. 1, the federal government will partially shut down. (The last time the government was forced to close was late 1995/early 1996, when President Clinton and congressional leaders could not compromise on a spending bill. That partial shutdown lasted 21 days.)

Related: Government Shutdown Risk is Real as Republican Minority "Blackmails' the House: Holtz-Eakin

Congress and the White House are also at odds over raising the debt ceiling – the government’s legal authority to borrow more money. The debt limit, which currently stands at $16.7 trillion, expires in mid-October; it has been raised 13 times since 2001. Treasury Secretary Jack Lew admonished Congress last week for playing games with the nation’s finances.

"Trying to time a debt limit increase to the last minute could be very dangerous," Lew said. "Make no mistake: If Congress does not act and the U.S. suddenly cannot pay its bills, the repercussions could be serious. The impact on families and businesses could be significant. Investors losing confidence in the full faith and credit of the United States could cause damage to our economy."

Yahoo News political reporter Chris Moody tells The Daily Ticker that Republicans are “playing with fire” by using the debt ceiling and the budget as mechanisms for delaying or permanently repealing the Affordable Care Act, a.k.a. Obamacare. Republicans are very determined to postpone Obamacare, even if a defunding measure will not pass in the Senate; Moody expects a “real fight” over the issue in the coming days and weeks.

“Republicans are shooting for the stars and hoping to get the moon here,” he says. A delay in the implementation of Obamacare “is the real sweet spot. We could quite possibly see an old-fashioned filibuster where guys like Sen. Mike Lee and Sen. Ted Cruz stand on the [Senate] floor for hours and hours.”

Pres. Obama reiterated his refusal to negotiate with GOP leaders over raising the debt limit this weekend.

“Let me say as clearly as I can: It is not going to happen. We have come too far. We have overcome far darker threats than those,” Obama said Saturday at the Walter E. Washington Convention Center.