L. Ray Roberts, left stands with his daughters Helena Roberts, 11, center, and her sister Cassie Boyle, 8, right, all from Pittsburgh, on the steps of the Supreme Court in Washington, Wednesday, March 4, 2015, as the court hears arguments in King v. Burwell, a major test of President Barack Obama's health overhaul which, if successful, could halt health care premium subsidies in all the states where the federal government runs the insurance marketplaces. The sisters are holding pictures of their grandmother Hannah Brown, who died when she was 58 years old. Their grandmother lost her job and healthcare and died a year and half later because of lack of access to treatment. (AP Photo/Pablo Martinez Monsivais) L. Ray Roberts, left, stands with his daughters Helena Roberts, 11, center, and her sister Cassie Boyle, 8, right, on the steps of the Supreme Court in Washington as the court hears arguments in King v. Burwell on March 4, 2015. (Pablo Martinez Monsivais/Associated Press)

GOP House and Senate leadership are bent on repealing Obamacare in January, cutting off its funding and then delaying the repeal for a few years until they can come up with something to replace it. If they go into the 2018 election with no health-care substitute passed, Republicans are likely to take a beating from voters who feel that they’ve “lost” health-care insurance and not gotten anything better. House and Senate leaders are convinced they can face the voters without a replacement and then pick up extra votes to pass it in an election in which Democrats must defend 23 seats. It’s not clear their members will go along.

If they do repeal and delay, we keep getting tripped up on the math. If the GOP tries to pass a health-care bill (beyond repealing funding that presumably can be done by reconciliation) before 2018, Republicans will need to pick up eight Democrats in the Senate (with a 50-50 tie, Vice President Mike Pence would then cast the deciding vote). What plan is going to appeal to eight Democrats without losing any Republicans? It would seem Republicans have an obligation to tell us what that plan is before repealing Obamacare.

Think about this. Are there eight Democrats who will vote for Obamacare without funding for abortion (eliminating abortion coverage is a must-have for Republicans)? We haven’t seen anything like that number of Democratic defections, for example, on Planned Parenthood funding votes.

Are there eight Democrats who will allow a major redesign of Medicaid and allow states to roll back coverage to pre-Obamacare levels? I don’t see Republican conservatives voting to reauthorize an expanded Medicaid that “rewards” blue-state governors who chose to expand Medicaid and need the feds to keep funding it.

Republicans have generally favored a tax credit to replace subsidized health-care coverage purchased in the exchanges. They will have to face up to the nettlesome problem: Do they vary the amount of the tax credit by income (thereby penalizing the working poor when they earn more and lose the subsidy), or do they give tax credits to billionaires (like the ones in Trump’s Cabinet)? Democrats could make a fuss either way.

Will eight Democrats eliminate the individual mandate and accept the idea that health-care insurance is only available, not required? (Democrats have been boasting about the increase in the number of covered Americans. The number could be much smaller without the mandate.)

There are lots of these tough issues and while Democrats say they will go along with “reforms” when faced with the prospect of something that looks much less certain than Obamacare or dramatically alters Medicaid or cuts out abortion coverage, those amenable Democrats will suddenly become terribly unhelpful.

Remember that bidding for Democratic votes with Trump in the Oval Office may be a hair-raising experience for Republicans. Maybe Minority Leader Sen. Charles E. Schumer (D-N.Y.) says to the new president: Make sure abortion funding is in there, put up a more moderate or older (or both) Supreme Court justice, and we’ll give you the votes for something that winds up looking much like the old Affordable Care Act? (But you “win,” President Trump!)

The risks for Republicans, in other words, become real if they take up the repeal and dawdle maneuver. They might never come up with something they can pass. They might lose seats in 2018 if they face the voters with Obamacare repealed and no replacement nailed down. They might open up a can of worms where Trump starts wheeling and dealing, ready to give Democrats most everything they want for the sake of a “deal.” (Think about Secretary of State John F. Kerry dumping concession after concession into the Iranians’ laps because failure was not an option.)

There are significant problem with Obamacare, some of which will get worse if Republicans repeal it in January (e.g. insurers will flee the exchanges). Republicans should address those in a bipartisan way or put all their cards on the table (i.e. put out the replacement plan) now so voters can see if there are now or will ever be enough votes for Trumpcare.