There’s no question that Republican criticism has helped undermine support for President Barack Obama’s health plan. But it hasn’t done much to help Republicans.

[IMGCAP(1)]That’s because while Republicans actually do have alternative ideas on health care reform, they have spent most of their time accentuating Obama’s negatives.

In fact, the negative so dominates GOP statements that an ordinary citizen could well believe that Sen. Jim DeMint (R-S.C.) represented the whole party when he said, “If we’re able to stop Obama on this, it will be his Waterloo. It will break him.—

And disruption by right-wing hooligans of town-hall meetings held by Democratic Members of Congress only adds to the impression that the GOP is merely working to defeat Obama.

In the CBS-New York Times polls in late July, 80 percent of respondents said the U.S. health care system needs “major reform.— Almost half said it needs “fundamental changes.—

Some Republicans in Congress have come up with reform plans, even “fundamental changes.—

But hardly anyone knows about them — partly, no doubt, because the media have ignored them. But it’s also because Republicans hardly ever mention them.

Moreover, in Congressional committee voting so far, while Republicans have offered amendments to Democratic proposals that indicate GOP thinking, they’ve not offered fully developed substitute plans that have been “scored— by the Congressional Budget Office.

Two interesting GOP proposals, so far not adopted by party leaders, have been offered from opposite ends of the Republican ideological spectrum — conservative and moderate.

They differ in one major way. Conservatives would end employer-based health care, while moderates would keep it.

But both are aimed, as you’d expect from the GOP, at using free-market competition to lower costs and making private insurance more affordable to businesses and individuals.

If and when the GOP decides to “go positive— on health care, it ought to make the case for the success of competition — the way a Democrat, former Clinton Commerce Department official Paul A. London, did in a recent Web article, “Lower Healthcare Costs: Learning From History.—

London wrote that Obama could cut costs by doing what Presidents Gerald Ford and Jimmy Carter did in the 1970s by removing price controls and otherwise deregulating such industries as air travel, trucking, telecommunications, energy, manufacturing, finance and retail.

London advocates, on the Web site theglobalist.com, opening current government health care monopolies — Medicare, Medicaid, the system and the Veterans Affairs Department — to competition among doctors, hospitals and insurance companies.

Republicans should be loudly advocating the same idea for national health care reform — and citing successful models like Switzerland’s system and America’s own Medicare Part D, the prescription drug program.

The conservative health care proposal has been offered in the House by Rep. Paul Ryan (Wis.) and in the Senate by Richard Burr (N.C.) and Tom Coburn (Okla.).

The moderate plan has been proposed by Reps. Mark Kirk (Ill.) and Charlie Dent (Pa.) and reportedly will form the basis of a full-blown GOP alternative developed by the GOP Health Care Solutions Group headed by Rep. Roy Blunt (Mo.), but not yet unveiled.

The Ryan-Burr proposal would allow employees to opt out of their employer-based insurance plan and get a $5,000-per-family tax credit to buy health insurance or pay medical bills.

It would also allow individuals and businesses to form pools and buy insurance anywhere in the country, not just in the state where they live.

As Ryan puts it, “This will greatly expand the choices of coverage available to consumers and will also encourage broader competition and diversity among insurers.—

Along with practically every other plan, Democratic and Republican, the conservative plan would require insurance companies to offer insurance regardless of a person’s pre-existing medical condition.

Meantime, Kirk and Dent’s Medical Rights and Reform Act is designed to lower the cost of insurance policies through legal reform — which will reduce the expensive practice of “defensive medicine— — and also create interstate pools.

According to Kirk, the average cost of insurance in states like California, which have limits on medical malpractice awards and allow large-scale pooling, is less than half that in lawyer-friendly states like New Jersey.

Both the conservative and moderate plans would allow low-income Medicaid patients to get vouchers to buy private insurance and encourage states to experiment with insurance market reforms.

Besides these proposals, other Republicans are cosponsoring bipartisan alternatives to Obama-Democratic plans, notably the Healthy Americans Act co-sponsored by Sens. Ron Wyden (D-Ore.) and Bob Bennett (R-Utah).

And, of course, in the only major bipartisan negotiation on Capitol Hill, three Republicans and three Democrats on the Senate Finance Committee are trying to hash out a health plan that can pass.

Despite all this action on the GOP side, Republicans rarely talk positively about how to fix the health care system but talk incessantly about what’s wrong with “Obamacare.—

The attack strategy certainly is working, up to a point. A Quinnipiac University poll released last week showed that the public disapproves the president’s handling of health care 52 percent to 39 percent.

At the same time, though, the poll showed that voters trust Obama to fix health care more than Republicans, 47 percent to 36 percent.

Last month’s NBC-Wall Street Journal poll showed that the public trusts Democrats on health care over Republicans 40 percent to 23 percent.

The CBS-New York Times poll found that 59 percent of voters think the White House is trying to work with Republicans on health care, while only 33 percent say Republicans are working with him.

They’re wrong, of course. In the main, neither party is working with the other — and, except in the Finance Committee, Democrats have utterly frozen Republicans out of the action.

But 73 percent of the public wants health care solved on a bipartisan basis, the CBS poll showed.

Democrats may want to ignore Republican ideas and label the GOP “the party of no,— but they’d have a harder time if the GOP were more assertive in pushing its positive ideas. Moreover, voters might think better of Republicans.