Republican candidates for Congress knew — or should have known — when they were promising to repeal President Obama’s health care law that it would never happen.

Now, many of the candidates who railed against health care reform while campaigning last summer and fall have taken office and they are making a show of trying to keep their promise.

Unfortunately, the exercise in promise-keeping is as phony as the promise was in the first place.

The Republican-controlled House of Representatives will debate and vote on a bill this week that, theoretically, would overturn the health care reform plan passed by Congress and signed into law by Obama.

We say “theoretically” because the repeal measure has little or no chance of being adopted by the Senate, and absolutely no chance of being signed by the president. Obama has pledged to veto any such bill that might arrive on his desk, and Republicans don’t have the votes to override a veto.

Don’t misunderstand. We don’t like “Obamacare,” as some refer to it. We supported the general concept of health care reform and even endorsed portions of an early version of the bill that was recommended by the Senate Finance Committee.

But we were highly critical of the law that Democrats eventually rammed through the Congress and we vigorously objected to the backroom wheeling and dealing that led to its passage.

The bill itself suffers from a number of flaws, including imposition of severe financial and paperwork burdens on small businesses. And we never bought into the idea that the plan would pay for itself; this new health care plan is destined to become one more untenable entitlement program that over time will add to the ever-growing, crippling burden of debt facing American taxpayers.

Those grim facts don’t change reality. If there were any hope of repealing the health care law and replacing it with something better, we would sign on to the effort; but the repeal bill is a waste of time — Congress’ time and the country’s.

Instead of pretending to keep a campaign promise by fostering the illusion that they can make Obamacare disappear, Republicans should be working with Democrats to repair the law’s most egregious shortcomings.

Even some Democrats who voted for the plan concede that it could be improved — and we would guess that others are politically astute enough to realize that many Americans want to see less desirable elements of the law corrected before it is fully implemented.

Republicans clearly believe that voters gave them a House majority and additional seats in the Senate last November because the country was fed up with Obama’s policies and Democratic rule in Congress.

That’s true, to some extent, but more than a changing of the guard, Americans were voting for a change of attitude. The country was tired of watching problems fester while those elected to find solutions opted instead to engage in political posturing and obstructionism.

Republicans were not put in charge of the House so they could stage a non-reality TV show on C-SPAN under the guise of repealing health care reform.

Serious and urgent problems await congressional action, including a looming national debt crisis and a naggingly slow recovery from the recent recession.

The United States is fighting two shooting wars and a perpetual battle against the threat of terrorism. The country remains hamstrung by our dependence on foreign oil. Immigration reform has long been a front-burner issue and will continue to be.

The list is long. There is no time to waste.

So why are we wasting time trying to repeal a law that cannot be repealed?