Democrats hope to retake the House of Representatives in next year’s elections. They won’t — and they’ll have themselves to blame, because 2014 is when ObamaCare kicks in.

With a vengeance.

The authors of the Obama health law postponed the pain until after the 2012 election. Some popular provisions went into effect immediately, such as allowing children to stay on their parent’s plan until age 26. And the White House granted 1,472 waivers to various companies and unions, exempting them from insurance reforms so they wouldn’t drop coverage for employees and members before the presidential contest.

Yet a majority of voters on Election Day still opposed the health law (though, obviously, it wasn’t the deciding issue in the presidential race). And opinion will only sour more as the law takes full force starting in January.

People in their 20s and 30s will be clobbered — their health-insurance premiums will double (or more), insurers report. Nineteen percent of the president’s 2012 voters came from this age group. The biggest problem: The Obama law forces insurers to charge young, healthy people more to cover the cost of insuring the middle-aged and those with pre-existing conditions.

Middle-aged folks will benefit somewhat from overcharging the young, but the law’s mandatory benefits package and its billions in new taxes on insurers will drive up costs enough that overall premiums for a family of five will start at $20,000 (before subsidies, if any). Oh — and that doesn’t count the penalty for each smoker, roughly $3,000 a head.

(Subsidies may help some people cover sky-high premiums, though not the smoking penalty — but the letter of the law makes those subsidies unavailable in many states. The federal courts will eventually decide the issue.)

Many workers in industries such as retail, hospitality and home care will lose on-the-job health coverage, forecasts the ADP Research Institute — and many will also be demoted to part-time status because of ObamaCare.

Why? The president’s health law mandates that all employers with 50 or more full-time workers provide its “essential benefit package” if they offer insurance — and that package costs about twice what these industries now offer. Many employers will drop coverage, and pay the (smaller) fine; others will try to avoid that 50-employee limit by using more people part-time.

Even the government’s actuaries admit fewer people will get coverage at work after the employer mandate goes into effect than if the law had not passed.

The IRS and the Department of Health and Human Services are now rolling out thousands of new regulations to implement ObamaCare — and employers are franticly trying to learn what “affordable” coverage and “full time” worker mean and what compliance will cost. The latest surprise, from HHS, is a$65-a-year feeemployers must pay for each employee or dependent they insure.

Seniors needing hospital care will be shocked at cutbacks. Section 3000A of the law awards bonus points to the hospitals that spend the least per senior. Hospitals are even whacked for what Medicare patients consume in the 30 days after discharge, including physical therapy.

Hospital patients of all ages will wait longer for a nurse. Cuts to Medicare pay for over half the law, and this will mean $247 billion less for hospitals over the next decade; the layoffs are already starting.

Other chaos will abound. Consumers trying to get their insurance from a state exchange will have to hand their Social Security Number and 15 pages of financial and family information to exchange “assisters” — temps often hired from community groups. In California, civil-rights activists are fighting to prevent background checks for would-be “assisters” because it would disqualify too many minority men with prior convictions.

Since only Democrats voted to impose ObamaCare on America, there’s no question who voters will blame for this colossal mess. The chances for a new Pelosi speakership are minuscule; we’re more likely to see Republicans win control of the Senate.

The GOP only needs to pick up six Senate seats to do that — and three seats the Republicans will target are in Iowa, Virginia, and Arkansas — the states set to be hit with the highest premium increases in the individual market.

Of course, all that may not be enough to repeal ObamaCare — it may take a few more elections before the will of the people prevails. But the system the Obama health law sets up is so dysfunctional, there’s an excellent chance voters will persevere until they get their way.

It’s not over til it’s over.

Betsy McCaughey, a former lieutenant governor of New York, is author of “Beating ObamaCare.”