WASHINGTON » If Republicans were writing a movie script for next year’s congressional elections, the working title might be "2014: Apocalypse of Obamacare."

The plot: The rollout of President Barack Obama’s health care law turns into such a disaster that enraged voters rebuke him by rewarding the GOP with undisputed control of Congress.

But there’s a risk for Republicans if they’re wrong and the Affordable Care Act works reasonably well, particularly in states that have embraced it. Republicans might be seen as obstinately standing in the way of progress.

The law already has been a political prop in two election seasons, but next year will be different.

Voters will have a real program to judge, working or dysfunctional. Will affordable health care finally be a reality for millions of uninsured working people? Or will premiums skyrocket as the heavy hand of government upends already fragile insurance markets for small businesses and individuals?

"The end of this movie has not been written," said Robert Blendon, a Harvard professor who tracks public opinion on health care. He says next year’s movie actually will be a documentary: what happens in states that fully put the law in place and those that resist — "a message of reality."

One of the most prominent doomsayers is Senate Republican leader Mitch McConnell of Kentucky, who predicts "Obamacare" probably will be the biggest issue of 2014 and "an albatross around the neck of every Democrat who voted for it."

"This thing can’t possibly work," says McConnell. "It will be a huge disaster in 2014."

Counting on that, House Republicans are busy framing an election narrative, voting to repeal the health law and trying to link it to the scandal over the Internal Revenue Service’s targeting of tea party groups. It could help excite the conservative base.

But Democratic pollster Celinda Lake doubts reality will follow the GOP script. Next year, "we won’t have to worry about the mythology laid out by the right wing about Obamacare: death panels and dramatic cuts to Medicare," she said.

Sen. Patty Murray, D-Wash., said uninsured people in her state will have over 200 coverage options to choose from. "We have been hearing the fear, but in states like mine, people are seeing the reality," she said.

In just about five months, people without access to coverage through their jobs can start shopping for subsidized private insurance in new state markets. The actual benefits begin Jan. 1. But because of continuing opposition to the law from many Republican governors and state legislators, the federal government will be running the insurance markets in more than half the states.

Another major element of the law, the expansion of Medicaid to serve more low-income people, also has run into problems. With many legislative sessions over or winding down, it looks like fewer than half the states may accept the expansion. That means millions of low-income people are likely to remain uninsured, at least initially.

Other early indicators of how well the health care rollout might fare are mixed.

In a dozen or so states that have started releasing details of their new insurance markets, there’s robust insurer interest in participating, according to the market research firm Avalere Health. That’s a good signal for competition.

There still are concerns about a spike in premiums for people who already buy their own coverage, particularly the young and healthy. That could happen for several reasons.

The health care law forbids insurers to deny coverage to sick people, and it limits what older adults can be charged. Also, the plans that will be offered next year are more comprehensive than many bare-bones policies currently available to individuals.

Another big source of angst is the Obama administration. The Health and Human Services Department will be running the program in half the country while trying to fight off attempts by congressional Republicans to starve it financially. Unusual for a social program, the administration is largely operating behind a veil of secrecy.

Will Obama’s underlings turn out to be the Keystone Kops of health care?

Frustration that he and his constituents couldn’t get basic information from the administration led one of the authors of the law, Sen. Max Baucus, D-Mont., to warn recently that he sees "a huge train wreck coming down."

Republicans loved it. Lost in the uproar was the fact that Baucus was referring to potential problems with implementation. He stills thinks the health care law itself is a good thing.

The administration official running the rollout, Gary Cohen, told Congress this past that he didn’t agree with the senator’s statement. "We are very much on schedule," Cohen said.

Republican pollster Bill McInturff says he’s skeptical of what he hears from the administration as well as from his own party. McInturff, who has made polling on health care his specialty, says the launch of any national program is bound to have problems. President George W. Bush’s Medicare prescription benefit went through several weeks of chaos before things got smoothed out.

"Life experience says to me there is not going to be some simple, clear narrative that is sitting here today," McInturff said.