The Senate debate on health care, set to begin the week after Thanksgiving, is now on course to collide with the holiday season. One question for advocacy groups on all sides will be whether to keep up their barrage of pointed commercials, even as chestnuts roast and stockings are hung.

The presidential primary candidates faced this same dilemma two years ago, when the Iowa caucuses were moved up to Jan. 3. The campaigns had to figure out how to stay visible during the crucial weeks before the vote, which overlapped with Christmas and New Year’s, when the public was not really up for a political brawl.

Rather than go dark, most of the primary candidates dropped their attack ads and softened their messages.

That experience may provide some guidance now, as health care advertisers mull their options along with their cider.

Much at Stake

All sides in the health care debate have already spent a combined $170 million on television advertising so far this year — the most ever spent on single-issue advocacy commercials in one calendar year, said Evan Tracey, chief operating officer of the Campaign Media Analysis Group, which tracks television advertising.

With so much at stake, neither side is likely to leave the airwaves just because of the holidays. The Senate will be debating until the Christmas break. And even if it manages to pass a bill before then, it would still need to produce a final bill with the House, which means the debate will almost certainly spill over into the new year.

“We will remain fully engaged,” said R. Bruce Josten, the chief lobbyist for the United States Chamber of Commerce, the primary sponsor of advertising against a health care overhaul.

The chamber, which has enlisted the support of numerous conservative groups, has fired off more than $24 million worth of advertisements in the last 30 days alone, arguing that an overhaul would cost jobs, raise taxes and increase the deficit in a shaky economy.

Supporters of an overhaul, meanwhile, led by labor and affiliated liberal organizations, spent about $14 million in the same period, arguing that an overhaul would make health insurance more affordable and accessible and thanking members of the House who voted for the bill on Nov. 7.

The two sides have much more on the way, and yet they are only beginning to grapple with how to adapt these messages to the holidays. One of the big factors at this time of year is the clutter of holiday promotions on television. But some on Madison Avenue say the holidays provide an opportune moment.

“It’s like when a department store has a white sale around a holiday,” said Richard Kirshenbaum, a branding expert and advertising executive. “Any time you have a national moment where people are getting together, it’s a way to open a dialogue, whether it’s about potato chips or health care reform.”

In 2007, Mike Huckabee, a Republican and a Baptist preacher, was the first presidential candidate to tailor a new message for Christmas. Others followed his lead.

Leading the Way

The path-breaking candidate before the presidential primaries was Mike Huckabee, a Republican and a Baptist minister, who was the first in 2007 to tailor a new message for Christmas.

Wearing a red sweater, he identified with viewers who had been besieged by political advertisements: “Are you about worn out from all the television commercials you’ve been seeing?”

Then he branded himself the evangelical candidate, in a direct appeal to his base: “What really matters is the celebration of the birth of Christ and being with our family and our friends.”

Other candidates followed his lead but avoided religious references.

Barack Obama’s commercials dropped his campaign theme of ending the war in Iraq and instead showed him in a cozy setting with his wife and daughters.

Hillary Rodham Clinton opened presents, one of which was labeled “universal health care.”

Hopes and Fears

A positive message of supporting a health care overhaul may lend itself more easily to the soft sell than would a negative message opposing it.

“Fear is not a holiday message, and that’s what they’re selling,” said Robert Creamer, a political consultant to liberal groups that support the overhaul. “To the extent that the holidays dispose people toward hope and possibility, that’s a good thing for us.”

Of course, not all of the opponents’ advertisements are negative (some thank the House members who voted against the bill) and not all of the supporters’ are positive (many criticize the influence of the insurance industry).

As a rule, experts say, the advertising between Thanksgiving and New Year’s Day should make people feel good rather than bad, even though that flies in the face of studies showing that negative commercials are often more effective in politics.

“Corporate brands always change their message during the holidays to tone down the rhetoric, to get people into the stores or to feel good about their brands,” Mr. Tracey said.

“It will be interesting if we see combat ads over health care mixed in with Rudolph the Red-Nosed Reindeer,” he said. “I would think very hard before I tied those two things together.”

MEANWHILE, TACTICAL PLANNING IN THE SENATE

Even as senators head home for the Thanksgiving recess, they will be thinking ahead to the parliamentary weapons for use in the debate on the Senate floor when they return to Washington.

Some of the clashes will be for show, intended to appeal to various constituencies watching on C-Span. But much of the parliamentary arsenal will be employed with a purpose — stripping out the proposed government-run insurance plan, for instance, adding tougher language on medical malpractice lawsuits, or tightening restrictions on insurance coverage for abortions.

Read David M. Herszenhorn’s guide to the gimmicks and gambits.