Kevin Lamarque/Reuters

Updated 3:04 p.m.

President Obama has been so publicly introspective and abashed of late that it's easy to forget his history as an exceedingly good campaigner. He's a politician who can make a hell of a case when he wants to—which is what he's about to start doing on behalf of the Affordable Care Act.

For weeks, the White House has been itching to fight back against Republican criticism of the president's signature achievement and what it sees as a GOP effort to harken back to an imaginary pre-Obamacare world of perfect insurance arrangements, where no one ever got dropped by a plan or excluded from coverage.

Now that Healthcare.gov, the portal for purchasing insurance in 36 state exchanges, is largely functional, the White House wants to remind people what the bad old days looked like—and what they'd have to face if Republicans succeeded in repealing the Affordable Care Act or gutting its key provisions. The best way to defend Obamacare, the thinking goes, is to remind people of the alternative.

Obama gave a base-rallying speech Tuesday at the White House in front of an enthusiastic audience to kick off a virtual advent calendar of daily healthcare-related messages touting the goodies in the ACA.