President Barack Obama has not been, at least in public, freaking out about the election of Donald Trump. If anything, his insistence on giving the president-elect a chance has frustrated many of Obama’s own supporters, who were hoping to see a validation from the president that (as the catchphrase has gone) “this is not normal.”

They just got that moment. Kind of.

During his last press conference Wednesday afternoon, Obama sent a message to “Democrats and progressives.” He urged them to distinguish between “the normal back-and-forth, ebb-and-flow of policy” on issues like whether taxes should go up or down and what climate policy would be, and conflicts that are, well, not normal:

But there’s a difference between that normal functioning of politics and certain issues or certain moments where I think our core values may be at stake. I put in that category, if I saw systematic discrimination being ratified in some fashion. I put in that category, explicit or functional obstacles to people being able to vote, to exercise their franchise. I put in that category institutional efforts to silence dissent or the press. And for me at least I would put in that category, efforts to round up kids who have grown up here and for all practical purposes are American kids and send them someplace else. When they love this country, they are our kids, friends, and classmates, and are now entering into community colleges and in some places serving in our military.

This isn’t just an academic distinction for Obama. He’s drawing a bright line: If President Trump does any of these things, Obama himself will be compelled to get back into the arena to defend them.

Obama said today (as he has in the past) that he’s planning to take, at very least, a vacation from public life after handing the presidency over to Trump; "I want to be quiet a little bit and not hear myself talk so darn much,” he said at the press conference.

And while he’s hinted in the past that he might see the need to step back into the arena to defend his legacy, he hasn’t specified (certainly not in public) exactly what would lead him to get back in. Now he has: “systematic discrimination”; efforts to suppress voting rights; efforts to silence the press; and deportation of the immigrants who Obama protected under the Deferred Action for Childhood Arrivals program.

In large part, this is because there’s a norm that presidents don’t go around criticizing their successors; as George W. Bush said of Obama in 2009, “he deserves my silence.” Obama, who’s always been committed to norms of upright behavior in politics, is aware of that. But he also appears to be aware that if he sticks too closely to the norm of silence, other norms might go undefended.

It’s not entirely clear what would constitute, say, “efforts to round up” deferred-action recipients — whether Obama would object to revoking their protections, or whether he’d only speak out if the Trump administration made a deliberate effort to track down and deport the same immigrants Obama had protected. But by laying out, in detail, the things that he views as not normal — as threats to American values that go beyond the “ebb and flow of policy” — Obama just drew a line in the sand and warned his much-less-popular successor not to cross it.