WASHINGTON — Lawmakers are not usually eager to get back to the nation's capital after a weekend in their districts, especially during campaign season. But Rep. Michele Bachmann boarded a flight from Minnesota on Sunday night — even though the House will not meet until Tuesday — to make sure she would not miss the Washington moment she has been excitedly anticipating: the Supreme Court ruling on President Obama's health-care law.

"The decision on Obamacare goes well beyond health care," Bachmann, a Republican and a vocal opponent of the law, wrote in an email. It "will determine whether or not the court believes the government has a right to mandate that Americans buy a product or service, a direct impact on our freedom and liberty."

The impending ruling has become this city's O.J. Simpson verdict crossed with a papal conclave — polarizing, maddeningly unpredictable and shrouded in mysterious signaling.

The ruling is expected this week, either shortly after 10 a.m. EDT Monday, the last scheduled day of the term, or on an extra day later in the week.

For members of Congress, health-care lobbyists, campaign officials and thousands of lawyers who populate the squat office buildings across the District of Columbia, the wait for the fate of the health-care law has become all consuming.

They constantly check Scotusblog, a website devoted to the doings of the court. They play Health Reform Bracketology, a website where they can choose among various possible outcomes.

Coming at the crest of a contentious presidential campaign, the decision will be the beginning of the end of one of the most divisive policy battles in decades, one that helped set off the tea-party movement and became the central conflict in the raging political war between Republicans and Democrats over the proper role and scope of government.

"This is such high drama," said Andrew Rosenberg, a partner specializing in health care at Thorn Run Partners, a government relations firm. "Because you have this decision that everybody knows was made months ago in a town that notoriously does not keep secrets well with such unprecedented implications for one-sixth of the economy."

For health-care advocates and others who work in the world of health-care policy, it is a bit like waiting for a baby to arrive.

Karen Davenport, the director of health policy at the National Women's Law Center, says it is "the first thing I think about when I get up in the morning" and the topic she spends most of her day talking about with colleagues.

The two most engaged groups are probably those made up of people who have spent their entire professional lives working on health-care policy and House Republicans, who have devoted much of the 112th Congress to trying to overturn or defund various aspects of the law.

Bachmann instructed her staff to reserve space at the House triangle — a spot of green outside the House side of the Capitol — where she plans to hold a news conference within 90 minutes of the decision. After that, she plans to head to the Supreme Court to join tea-party groups who are expected to gather there.

For the past eight weeks, members of House Speaker John Boehner's staff have met with their counterparts from the office of Sen. Mitch McConnell of Kentucky, the Senate minority leader, to devise a game plan for their response.

Over the past few weeks, representatives from Mitt Romney's presidential campaign have been brought into the loop as well.

No matter the outcome, Republicans are expected to push forward with legislation to repeal the law.

Boehner, however, cautioned House Republicans in a memorandum last week not to seem too joyous if all or part of the law was struck down.

"We will not celebrate at a time when millions of our fellow Americans remain out of work, the national debt has exceeded the size of our nation's economy, health costs continue to rise, and small businesses are struggling to hire," he wrote.

Democrats are coordinating far more loosely, according to several media operatives on Capitol Hill, under the notion that they expect the law to be upheld. A spokesman for the White House declined to discuss post-decision plans.

At a Democratic caucus meeting last week, Sen. Harry Reid of Nevada, the majority leader, was peppered with questions about the ruling from anxious senators. He responded that there should be less fretting about things they cannot control, an attendee said.

Scotusblog — the TMZ of the legal world, not officially recognized by the court — has rewritten its software and moved its popular live blog to a new server to accommodate the expected traffic.

The blog will have seven people working full time, compared with the usual two. "We will keep the live blog up so people don't have to refresh," said blog publisher Tom Goldstein.