WASHINGTON — President Barack Obama is embarking on a final public relations push on health care today before heading off on vacation, wading into the same kind of often hostile town meetings that members of Congress have endured for much of August.

Obama heads to Montana today and Colorado on Saturday for town hall meetings even as his allies are stepping up their efforts to counter what they describe as “myths” about health-care reform. Obama supporters are being urged to turn out for the president to counter what they anticipate could be the kind of vocal criticism that has dominated headlines and cable news in recent days.

Facing questions about whether public support for the health overhaul initiative is sagging, White House press secretary Robert Gibbs said Thursday that the problem is rooted in misconceptions spread by political opponents.

“Have some of those misconceptions contributed to the poll numbers? I don’t doubt that,” Gibbs said. “But at the same time, I mean, there’s a little cause and effect here, but we’re not going to stop pushing back on the misconceptions, whether or not the polling shows one thing or another. The president, again, strongly believes that, and has for years, that it’s better to address what people’s concerns are and take them on head on.”

Separately, a coalition of groups backing Obama’s proposals launched a $12 million TV ad campaign Thursday, pitching health insurance reform in states where centrist Democratic House members or senators are under pressure on the issue. The campaign is intended to serve as a counterweight to critics who have shouted down Democratic lawmakers at town hall meetings, encounters that have received heavy news coverage.

The coalition distributing the ads, called Americans for Stable Quality Care, is funded largely by the pharmaceutical industry and includes the American Medical Association, FamiliesUSA and the Federation of American Hospitals, as well as Pharmaceutical Research and Manufacturers of America, the lobby known as PhRMA, and the Service Employees International Union. PhRMA has promised to contribute as much as $150 million for advertising and grass-roots activity to help pass Obama’s health-care reform package.

According to a USA Today/Gallup poll, 69 percent of Americans are closely following news of town hall meetings on health-care reform. Thirty-four percent say protests against the plan have made them more sympathetic to critics’ views, while 21 percent say the protests make them less sympathetic. Thirty-six percent say the protests have made no difference either way.

A separate USA Today/Gallup poll reported that 49 percent of Americans disapprove of Obama’s handling of health-care policy while 43 percent approve.

With Obama heading to Montana, that state’s Democrats are furiously recruiting the party faithful to turn out at his event, which is scheduled to take place near Bozeman. Demonstrators targeting Obama’s appearance view it as their best opportunity yet to make their case against a plan they perceive to be a government takeover of health care.

Worried about the potential for a harsh reception, the Montana Democratic Party sent out an e-mail alert to supporters Thursday urging them to show up today.