Updated 9/10/2013 at 1:48pm
Washington (CNN) - It's been pushed off the radar the past couple of weeks by the 24/7 media coverage over whether Congress should authorize a military strike against Syria, but the bitter partisan battle over the new national health care law claws its way back into the spotlight on Tuesday.
Proponents of the drive to defund the Affordable Care Act, better known as Obamacare, take to the West Lawn of the U.S. Capitol to hold an afternoon rally. A couple of hours earlier supporters of the law held their own gathering on Capitol Hill to push back against what they call Republican attempts to "sabotage" the health care law.
The events come as the clock ticks down to key elements in President Barack Obama's health care law taking effect. Enrollment in the health care exchanges that form the core of the Affordable Care Act begins October 1, and members of Obama's administration have been hurriedly pitching the marketplaces to healthy young people, whose participation is necessary for rates to remain low.
The rally to defund Obamacare was organized by two conservative groups, the Tea Party Patriots and ForAmerica, which last month held events across the country to pressure Republican members of Congress to join the push to defund the health care law.
Three GOP senators who are leading the defund charge, Ted Cruz of Texas, Rand Paul of Kentucky, and Mike Lee of Utah, are all scheduled to speak at the rally. The three senators, as well as some other conservative lawmakers, are using upcoming budget battles as leverage, vowing to oppose any measure that provides funding for the federal government, including money for the health care law. The measure funding the federal government expires September 30, setting up another Capitol Hill budget battle between congressional Republicans and the White House.
But so far only slightly more than a dozen fellow Republican senators have signed up to support the cause, leaving it up to outside conservative groups to rally the base.
That's the purpose of Tuesday's rally, as well as other events by grassroots conservative groups, including a nine-stop series of townhalls held the past few weeks by Heritage Action, the sister organization of the Heritage Foundation, one of the oldest and largest conservative think tanks.
"This fight is about backbone and we need some backbone up here, we need some help," Paul told the crowd. "We may not win the ultimate battle but we won't know unless we begin and fight the battle. I say fight on, don't give up, this battle can yet be won."
House Republican leaders Tuesday introduced to the GOP rank and file legislation that would fund the government through mid-December. In an attempt to give conservative members cover and to secure votes, Republician leaders are also drafing a proposal that would be voted on alongside the funding bill. The separate measure would contain language preventing the administration from using any federal funds to implement the new health care law. A House vote on both these measures could come as early as Thursday.
A senior House GOP aide admitted to CNN Monday night that the language on defunding Obamacare would be non-binding.
"Listen, our goal here is not to shut down the government, " House Speaker John Boehner said at a briefing with reporters Tuesday after a closed-door policy meeting with Republican representatives. "Our goal is to cut spending and stop Obamacare. I believe that the strategy that was outlined to the members this morning accomplishes that."
Asked about criticism from some Republicans that the suggestion of a separate vote on defunding the health care law seemed like a gimmick to appease conservatives, Boehner said "We've just initiated those conversations this morning. We'll be talking to those members as the day goes on."
Both Boehner and House Majority Leader Eric Cantor were booed by many at the defund Obamacare rally.
Preceding the anti-Obamacare rally was an event at the U.S. Capitol visitors center organized by two progressive groups, Americans United for Change and Protect Your Care, to "denounce GOP efforts to sabotage the health law and leave millions uninsured," according to a release. A handful of Democratic lawmakers were also attending the gathering.
"We are going on offense on Obamacare. We are no longer sitting around and let Republicans kick a law that we know is going to work," said Americans United for Change president Brad Woodhouse.
The battle over Obamacare and the new attempts to defund the law were generating headlines as Congress headed into recess in early August. Other than former President Bill Clinton's speech last week in defense of the measure, however, the story's been mostly pushed to the sidelines by the constant coverage of a possible U.S. military strike against the Syrian government for their alleged use of chemical weapons against its own citizens.
- CNN White House Producer Kevin Liptak and CNN Producer Paul Courson contributed to this report.