As congressional Democrats discovered late last year, tax breaks once bestowed are impossible to take back.

Now Republicans are determined to demonstrate another truism: Once Americans get their mitts on a government program, they hold on forever.

The newly emboldened GOP House leadership promises a vote soon on a bill repealing the Health Care and Affordability Act, also known as ObamaCare.

The law was passed last year by the slimmest of margins and after months of partisan wrangling. Having decisively won the mid-term elections, Republicans now feel obligated to at least try killing the new law.

The vote is necessary, even if everyone from Republican leaders down to first-term congressmen realize it is a symbolic gesture. Democrats still control the Senate and the presidency, and will block any effort to kill the new law.

But gestures and symbols are important, and the GOP has every right to proceed.

After that, however, Republicans are left with a less dramatic option: trying to kill or modify the law piece by piece.

While half of Americans say they don’t like ObamaCare, there are large and powerful constituencies for each of its major provisions.

For instance, the law plugs the drug “doughnut hole” for seniors with a 50 percent discount on brand-name drugs. Repeal would offend the largest and most vocal lobby of all, older folks.

The new law also provides free mammograms and cancer screenings for seniors, and a voluntary program to help seniors live independently outside nursing homes. Try taking that away.

The bill prohibits insurance companies from denying coverage to children who have pre-existing conditions and were formerly uninsurable. Anyone willing to kick those kids back off their parents’ insurance can sign up now.

The new law also allows adults to keep their children on health care policies until they are 26. Maybe Republicans can take that away, but it wouldn’t be pretty.

The law ends lifetime health insurance caps for policy holders with chronic or terminal illnesses. Ending insurance benefits for dying people? That would take some brass.

It’s more likely Republicans will vote, denounce the defeat, then move on to other issues.

They realize the one true hope of killing the new law resides in the courts, not in Congress.

Challenges to a provision “forcing” people to buy health care coverage are working their way toward the Supreme Court.

That provision is the bill’s Achilles’ heel, and Republicans know it.  When that provision fails, so does a major provision for paying for the law’s popular benefits.

With the funding mechanism dead, Congress will be left with an even bigger dilemma: a bunch of can’t-kill benefits voters really like and no way to pay for them.

Which, when you think about it, is largely the way government now runs.

Our health care system has been in crisis for more than a decade, and Republicans offered no solutions during eight years of the Bush administration, other than passing another costly benefit — prescription drugs for seniors — and then neglecting to pay for it.

Everyone agrees our health care system is unsustainable.

To be credible, Republicans must produce an alternative to ObamaCare. Simply killing the existing bill might be a crowd-pleaser, but it only takes us back to square one — a health care system we cannot afford.

editorialboard@sunjournal.com