There are still plenty of Republican candidates who imagine that they will sweep to victory this fall on a promise to repeal the healthcare reform legislation enacted earlier this year by the Democrats who currently control the House and Senate.

The Democrats can only hope that the repealers will raise their voice and be heard.

Why?

Because the pattern in the polling suggests that healthcare reform, imperfect as it may be, is gaining popularity at an exponential rate.

Indeed, more Americans now support the reforms pushed through Congress by the Democrats—against the opposition of the Republicans—than at any point since the Associated Press started polling on the question in September 2009.

Indeed, a plurality of potential voters now say Congress did the right thing, with 45 percent favoring the initiative to 42 percent opposing it.

That’s a dramatic shift in support for reform.

In the immediate aftermath of President Obama’s signing of the plan in March, following a raucous Congressional debate that saw Republicans portray relatively mild reforms as "totalitarianism," opposition spiked. By late April and early May, the reform package was opposed by a 46-39 margin.

At that point, as congressional Republicans were fresh from their appearances at April "Tea Party" events, there was a lot of talk about "running against reform" and "running for repeal."

Serious Republican strategists have for some time been counseling their candidates to suggest that they were for "repeal and replace"—a bow to the fact that reforms were needed and that many of them (protecting people with pre-existing conditions, allowing more flexibility when it comes to purchasing prescription drugs) remain extremely popular. But at a point when the Grand Old Party tends to be erring for to the right as it plots platforms for November, there is not much taste for nuance.

As such, Republican challengers in key races across the country continue to attack Democratic members of the House and Senate for moving to address the health-care crisis. In California, for instance, Republican Senate candidate Carly Fiorina still features a "Repeal It!" petition on her campaign website, with the candidate’s signature featured front and center. As recently as this week, Wisconsin Republican Ron Johnson, who is challenging Democratic Senator Russ Feingold, declared that: "The Health Care Bill is the greatest assault on our freedom in my lifetime.  It must be repealed.”

If the shift in public sentiment on the issue continues, however, Democrats will be wise to respond to the attacks on their votes by simply saying: "Why, yes, yes I did."

To the calls for repeal, their reply should be: "I don’t think so."

That’s the right response, of course.

But it is, as well, the smart political message.

Support for healthcare reform was always higher among women than men. In the past two months, however, support for reform has risen dramatically among men—from 39 percent in early May to 46 percent today.

Support among Americans who are in their prime working years—a key swing-voting bloc on this issue—has spiked. In early May, Americans in this 30-49 age group were exceptionally wary of reform. Only 35 percent of them favored what Congress had done. Today, 49 percent of them say Congressional Democrats did the right thing.

Remarkably, even Republicans are warming to reform. In early May, only 8 percent of self-identified Republicans said they agreed with what Congress had done with regard to healthcare. Now, the number has more than doubled to 17 percent.

By any measure, says Harvard University public health professor Robert Blendon, the Obama administration and its Congressional allies have improved their position in the period following the vote. "They are clearly making progress in convincing more Americans that this bill is the right way to go," says Blendon.

But it’s not just about this bill.

Perhaps even more significant are the numbers regarding specific reforms are the numbers regarding which party is trusted on healthcare issues.

In general, 51 percent of American now say trust Democrats to do a better job of responding to healthcare issues. Only 39 percent trust the Republicans.

That does not mean that Democrats are out of the woods on this issue. Even though 77 percent of Americans say healthcare policy is "personally important" to them, there are lots of other issues. In particular, lingering unemployment and deindustrialization in heartland states could depress turnout and support for Democrats in states where the party made some of its most significant gains in 2006 and 2008.

Even on the issue of healthcare, seniors, who vote in high percentages especially in mid-term elections, remain the age group that is most uncomfortable with the reform legislation as passed by Congress. Clearly, their concerns must be addressed.

But that may not be hard. If Republicans persist in making road calls for repeal of the reform, and if those calls are coupled with talk about cracking down on entitlements by Republicans such as Wisconsin Congressman Paul Ryan, a key player on budget issues, the GOP will stir uncertainty with regard to which party can be trusted to protect Medicare and Social Security.

Such uncertainty has, historically, benefitted Democrats.

The bottom line: in competitive House and Senate contests this fall, there is good reason to believe being on the side of reform will be a political positive for Democrats—not the negative that Republican strategists and many pundits imagined in March and April.

Smart Democrats will run as savvy backers of reform who talk about it as a first step and open dialogues with voters about how and where to take the next steps.

Those same smart Democrats will, as well, be hoping that they catch the lucky break of having Republican opponents who run as "party of No" opponents of any meaningful moves to repair of healthcare system that voters are coming to recognize as being in need of reform.