How seriously should Americans take the Republicans’ last-ditch effort to repeal and replace the Affordable Care Act?

The party has until the end of the month to repeal the health law without needing 60 Senate votes. That’s why the latest proposal, by Senators Bill Cassidy of Louisiana and Lindsey Graham of South Carolina, is getting so much attention.

Their bill would eliminate the two big coverage programs created by the Affordable Care Act (Medicaid expansion and the Obamacare marketplace) and instead give blocks of money to state governments, with few limitations on how they can distribute them to provide health coverage to their residents. States would be free to eliminate Obamacare rules requiring that insurance cover a minimum package of benefits, and they could charge sick customers more than healthy ones.

It would also make major changes to Medicaid, reducing federal funding even for populations that were covered before Obamacare. The results would most likely be substantial reductions in the number of Americans with health coverage, and new challenges for Americans with pre-existing health problems in some states.