With House Republicans and media figures alike berating President Obama for failing to fulfill a promise made four years ago, the president tried to set the record straight during a Wednesday rally in Boston.

“This has been the latest flurry in the news because there’s been a lot of confusion and misinformation,” Obama said. “I want to explain just what’s going on.”

“Anyone peddling the notion that insurers are canceling peoples’ plan without mentioning that almost all the insurers are encouraging people to join better plans with the same carrier and stronger benefits and stronger protections while others will be able to get better plans with new carriers through the marketplace and that many will get new help to pay for these better plans and make them actually cheaper,” he said. “If you leave that stuff out, you’re being grossly misleading, to say the least.”

NBC News produced what they billed (and Republicans seized on) as a blockbuster report this week: The administration has known for years that what Obama promised Americans in 2009 — “If you like your health plan, you can keep it” — wasn’t exactly true.

Never mind that, as Jonathan Cohn reported, this issue had already been litigated since shortly after the law had been passed. The story exploded. It became the GOP’s favorite line of questioning during Wednesday’s hearing with Health and Human Services Secretary Kathleen Sebelius. Media fact-checkers harangued Obama for misleading the public.

But more friendly figures, like House Minority Whip Steny Hoyer (D-MD), also said that the president had chosen his words poorly.

So Obama devoted a significant chuck of his Wednesday speech to explaining, as simply as something as complex as health insurance can be explained, what was happening.

“One of the things health reform was designed to do was to help not only the uninsured, but also the underinsured,” he said. “There are a number of Americans, fewer than 5 percent of Americans, who have got cut-rate plans that don’t offer real financial protection in the event of a serious illness or an accident. Remember, before the Affordable Care Act, these bad apple insurers had free rein every year to limit the care you received or use minor preexisting conditions to jack up your premiums or bill you into bankruptcy. So a lot of people thought they were buying coverage and turned out not to be so good.”

“Now, if you had one of these substandard plans before the affordable care act became law and you really liked that plan, you were able to keep it. That’s what I said when I was running for office. That was part of the promise we made.”

Here’s how experts explain the situation: The law allowed insurers to continue covering customers with pre-ACA plans, but they couldn’t enroll any new customers into those plans and they couldn’t make significant changes to them.

After a while, that stops making business sense for insurers and so they’ve been canceling those so-called “grandfathered” plans. The coverage that would replace it, as prescribed by the law, is usually much more robust and therefore priced differently, as Sebelius and other officials have said when asked about the issue.

Oftentimes, the base premium price is going to be higher, but it’s going toward much better coverage. On top of that, a lot of people — anybody making less than 400 percent of the federal poverty level — can receive some financial help through Obamacare to pay for new coverage they purchase on the law’s insurance marketplaces.

“Ever since the law was passed, if insurers decided to downgrade or cancel the substandard plans, we said under the law is, you’ve got to replace them with quality, comprehensive coverage, because that, too, was a central premise of the Affordable Care Act from the very beginning,” Obama said. “And today that promise means that every plan in the marketplace covers a core set of minimum benefits like maternity continuity and mental health care and hospitalization and they can’t use allergies or pregnancy or a sports injury or the fact that you’re a woman to charge you more. They can’t do that anymore.”

So, for Americans who have had their health plans cancelled for the above reasons, Obama urged them to visit HealthCare.gov and see what else would be available to them under Obamacare.

“The system is more secure for you and it’s more secure for everybody,” he said. “So if you’re getting one of these letters, just shop around in the new marketplace. That’s what it’s for.”