THE SENATE has been deadlocked on repealing and replacing Obamacare all month, but Majority Leader Mitch McConnell (R-Ky.) announced Monday afternoon that the chamber would vote Tuesday on . . . well, on something.

The scrambling reflected a basic fact: Every major Republican proposal put forward so far would mean millions of Americans would lose access to health care. Each plan would theoretically fulfill a GOP campaign promise while inflicting serious harm on the nation.

A bill drafted under Mr. McConnell’s guidance would repeal big portions of Obamacare, roll back Medicaid and slash help for those buying private health insurance. The nonpartisan Congressional Budget Office (CBO) found that the most recent version of that bill would result in 22 million more uninsured people in a decade, in part because it would dramatically hike deductibles for low-income people, who would not bother to buy insurance at all.

That same bill augmented by an amendment from Sen. Ted Cruz (R-Tex.) would do much more harm to the individual health-care market. Mr. Cruz would separate healthy insurance-buyers from sick ones, allowing the former to buy cheap, skimpy plans and forcing costs for the latter to go spiraling upward. Insurers warned lawmakers strongly that the Cruz language would severely disrupt individual insurance markets. And voting on such a potentially destabilizing measure before the CBO has even had a chance to analyze it would be breathtakingly irresponsible.

There is a bill that would kill much of Obamacare and replace it with nothing specific. Instead, the measure would delay the law’s death by two years, under the logic that Congress would feel compelled to pass some kind of replacement between now and then. The CBO found that this bill would result in 32 million more uninsured people in a decade, catastrophically unraveling individual health-care markets.

Then there are a couple of less-commented-upon GOP health-care proposals. One from Sen. Bill Cassidy (La.) and Sen. Lindsey O. Graham (S.C.) would give states enormous block grants with few requirements. Another, somewhat more promising option comes from Mr. Cassidy, Sens. Susan Collins (Maine), Shelley Moore Capito (W.Va.) and Johnny Isakson (Ga.), who would allow states that want to keep the Obamacare system to do so, while letting others take a more conservative path but within defined guardrails.

The proposals under consideration run the gamut from bad to horrendous, and the rushed process for proceeding to the floor has made a mockery of the “world’s greatest deliberative body.” The only proposal that could serve even as a template for a reasonable, bipartisan bill is the Cassidy-Collins-Capito-Isakson plan. But it has been sidelined since it emerged, and it would require weeks of negotiation to get it into shape.

Senators should reject Tuesday’s motion to proceed to debate on repealing and replacing Obamacare. Keeping an irresponsible campaign promise is not worth inflicting any of these “reforms” on the American people.