As so often, President Barack Obama recited case studies of those who will be helped by the Affordable Care Act.
But the standing ovation, from the carefully invited audience, came when he said, "We are not going back," and that while he was president, the law would not be repealed.
It is his strongest argument. At the moment Obamacare is still very vulnerable and Republicans will not let go of a good thing - they are expected to roll out a series of attacks, responding to fresh glitches or new weaknesses.
But they don't have a coherent plan. They look like "the party of 'no'".
They hate Obamacare, but they don't say what they would put in its place.
Few objective observers think the American healthcare system was working well before Mr Obama. It is too expensive and too many people are uncovered.
Even if the new law turns out to be really flawed, the people who've been given free care under states' expanded Medicaid schemes won't look kindly to anyone who wants to take it away from them.
It is maybe the wrong time in the political cycle to expect conservatives to come up with their own plans, but not having one may prove to be a liability.
Obamacare will probably suffer a lot more problems, but for now Democrats may feel confident enough to return to the attack.
Call it what you like, but this was a relaunch. Mr Obama apologised for the "poor execution" of the healthcare website, and said that any start-up this big would face problems - and they would be fixed.
But his main aim was to divert our gaze from the messy problems of the past onto the prize.
"Nobody should have to choose between taking their kids to the doctor and putting food on the table," he declared.