Once again, the Senate is focused on whether Republicans have enough votes to pass a repeal and replacement of the Affordable Care Act.
Sunday brought more signs that the chances for the Republican health care bill from Sens. Lindsey Graham of South Carolina and Bill Cassidy of Louisiana were dim when Sen. Susan Collins of Maine told CNN's Jake Tapper that it would be "very difficult for me to envision a scenario" where she would vote for the bill.
The latest GOP push to repeal and replace Obamacare had already hit what might be an insurmountable roadblock when Sen. John McCain on Friday again raised his hand and said no.
Texas Sen. Ted Cruz, considered to be a "yes" vote, said Sunday that the bill, as written, did not currently have his support.
However, Kentucky Republican Sen. Rand Paul, who has been a vocal and firm "no" vote, said Sunday that he might be able to support the measure, if the plan abandons the block grant funding program for states, the main tenet of the Graham-Cassidy bill.
Supporters vowed to keep fighting to prevent another GOP senator from joining McCain and, presumably, Paul in opposing the bill because three Republican votes against it would kill it.
All eyes now rest on Collins, who said she wanted to hear from the Congressional Budget Office before rendering her final decision -- which is expected to release a partial score on Monday -- and Alaska Sen. Lisa Murkowski.
On Sunday evening, the GOP released its latest version of the health care bill, which aimed to convince members who are still undecided to support the bill. The changes aim to increase funding for states like Alaska, but there's no proof that the bill will bring the undecided senators onboard now.
In one new provision particularly beneficial to Alaska, the state would receive a 25% boost in federal matching funds for Medicaid due to its defined high-level of poverty.
But despite the new version, there are still plenty of obstacles ahead.
In the meantime, the Senate finance committee has a hearing to examine the bill Monday afternoon. Progressive advocates plan to protest the hearing to show their support for preserving Obamacare.
GOP leaders must decide soon whether to press forward with a vote on the measure -- something that could be embarrassing if it is defeated. Still, Republicans might want to do it to put all senators on the record.
Republicans face a deadline Saturday when a special budget rule expires that would allow Republicans to pass a repeal on a party-line vote.
Another major focus for the week will be tax reform. The so-called Big Six gang of tax negotiators were already planning to release a "consensus document" this week that reflects their "core principles" that would outline a framework of the pending tax reform bill.
It's unclear how detailed the framework will be, but Republicans are eager to move forward on tax reform, desperate for a legislative victory before heading into next year's midterm elections.
But first they must pass a budget -- so they can use the same rules they tried with health care to pass tax reform without Democratic votes -- and they need to get the conservative House Freedom Caucus members on board. Releasing the framework is in part aimed at giving conservatives enough details on tax reform so that they'll sign onto a budget by the end of the month.
Republicans on the House tax writing panel -- the ways and means committee -- will meet this week to discuss several issues, including tax reform, while the full Republican conference will hold a retreat Wednesday to do the same.
Facebook is turning over the ads it sold to what turned out to be Russian operatives during the 2016 campaign to the congressional committees investigating charges of collusion between the Trump campaign and Russian officials. They don't plan to make these public, but more details on the content could come out this week.
Officials from social media giant Twitter will meet with Senate intelligence committee investigators Thursday.
Former Trump campaign adviser Roger Stone will appear Tuesday before the House intelligence committee.
All political eyes will be on Alabama where Republican Sen. Luther Strange takes on Judge Roy Moore, also a Republican, in the primary runoff for the Senate seat vacated by Attorney General Jeff Sessions. The GOP establishment in Washington -- including President Donald Trump -- is backing Strange but the outspoken conservative judge could still pull out a win.
Lawmakers will weigh needs for disaster relief as the situation in Puerto Rico and the US Virgin Islands becomes clearer. GOP leaders have pledged to pass additional aid to help these hurricane-stricken islands as well as previously-hit Texas and Florida.
Tuesday, the Senate judiciary committee will consider two separate bipartisan-sponsored bills that would protect Justice Department special counsel Robert Mueller from being fired. One bill from Graham and Sen. Cory Booker, a New Jersey Democrat, would require judicial review for Mueller to be removed as special counsel. The second bill -- sponsored by Sens. Thom Tillis, R-North Carolina, and Chris Coons, D-Delaware -- would allow Mueller to challenge his dismissal in federal court.
FBI Director Christopher Wray and acting Homeland Security Secretary Elaine Duke will appear before the Senate homeland security committee Wednesday to testify about threats to the homeland. Wray is also expected to face questions about the Russia investigation and whether the FBI warned Trump that his former campaign chairman, Paul Manafort, was being watched by the agency because of his dealings with pro-Kremlin figures.
Not a hearing, but still notable: Congress is also likely to pass a short term extension for the Federal Aviation Administration this week.