Polls consistently show that the Affordable Care Act remains unpopular with a substantial percentage of voters. Yet the law appears to be hurting Republicans more than Democrats.

That’s because the Republicans, who have controlled both chambers of Congress since January, have failed to rally around an alternative.

In April 2010, the month before the law was signed, 46 percent of all adults surveyed had a favorable view of the Affordable Care Act, according to the Kaiser Family Foundation’s regular tracking poll; 40 percent had an unfavorable view. The foundation’s July 2015 tracking poll showed the numbers largely unchanged, with 43 percent of adults viewing Obamacare favorably and 40 percent unfavorably.

That was actually an improvement: Every poll between February 2013 and March 2015 had shown the unfavorable rating exceeding the favorable.

The law has been rewritten many times since 2010. The two biggest rewrites were done by the Supreme Court in June 2012 and June 2015. The first redefined the penalty for not complying with the individual mandate to purchase health insurance as a tax, thereby rendering it constitutional. The latter extended access to tax credits to individuals who purchase insurance through the federal insurance exchange, ignoring the statutory language restricting credits to individuals who purchase insurance from a state exchange.

What these court decisions mean is that Obamacare likely is here to stay until a future Congress and president repeal and replace it.

One might think that this would lead the American public to throw in the towel and embrace Obamacare. But that hasn’t happened. Opposition remains firm. Yet, Republicans aren’t benefiting from this.

A July poll from the Pew Research Center asked respondents which party is better able to handle health care; 46 percent chose Democrats and only 36 percent Republicans.

Even President Obama is polling better on health care than Republicans, despite the lack of enthusiasm for the law bearing his name. He is still slightly upside down in the Pew poll, with 50 percent disapproving, versus 46 percent approving. However, his numbers are moving in the right direction. Last December, 56 percent disapproved and only 39 percent approved of his handling of health care.

The big move has been among young adults, aged 18 through 29, whose approval of the president on health care has jumped from 37 percent to 52 percent. This is remarkable given the fact that Obamacare has caused health insurance premiums to skyrocket for many young people.

The president bet that they wouldn’t notice because billions of dollars of tax credits disguise the full cost of their insurance. Apparently, he’s winning that bet.

Polling data over many decades consistently have shown that the public trusts Democrats more than Republicans on health care and other social-spending issues. But this gap was closing. In July 2004, 50 percent rated Democrats better able to reform the health care system, but during the Obamacare rollout the numbers started to turn. By September 2013, the Republicans actually edged out the Democrats, 40 percent to 39 percent, before returning to the 46 to 36 percent poll results favoring Democrats today.

It’s not hard to figure out why the GOP is slipping again on this issue. Since taking control of Congress, Republicans have focused on small changes to Obamacare, such as the so-called Medicare “doc fix” and the repeal of the medical device excise tax. While these and other things certainly need fixing, they are no substitute for replacing Obamacare.

While that isn’t possible with President Obama in the White House, the GOP could at least explain what its alternative would look like.

The best alternative would be a universal, “refundable” tax credit, which would enable individuals and families to purchase the kind of health coverage that best suits their needs, free of federal mandates and red tape. Can that really be such a hard sell?