On the presidential campaign trail, former President Donald Trump is, once again, promising to repeal and replace the Affordable Care Act — a nebulous goal that became one of his administration’s splashiest policy failures.

“We’re going to fight for much better health care than Obamacare. Obamacare is a catastrophe,” Trump said at a campaign stop in Iowa on Jan. 6.

The perplexing revival of one of Trump’s most politically damaging crusades comes at a time when the Obama-era health law is even more popular and widely used than it was in 2017, when Trump and congressional Republicans proved unable to pass their own plan to replace it. That failed effort was a big part of why Republicans lost control of the House of Representatives in the 2018 midterms.

Despite repeated promises, Trump never presented his own Obamacare replacement. And much of what Trump’s administration actually accomplished in health care has been reversed by the Biden administration.