After the clock struck eight, MSNBC pounced to make the call: Obama carries Washington, DC. Reuters followed not long after.

But wait. As TPM pointed out last night, no exit polls were taken in DC. And the district’s vote returns, perhaps slowed by the weather, took some time to trickle in. (When they did, there wasn’t much of a surprise. Obama won 75% of the vote.)

Still, isn’t it a bad idea to call an election with literally no information?

CNN thought so, warning viewers just that: they had no information, and that it would be a while before they felt comfortable making a call. Crazy, isn’t it.

Now, of course, MSNBC and Reuters did have some information: the city is overwhelmingly black, and DC’s white residents have more post-secondary degrees per capita than whites in any state. Both groups are Obama locks, and pre-vote polls showed him with a handy lead.

But it’s not like we found any of that out last night, just after 8 pm.

Win-loss results derived from exit poll data are, in theory, quarantined until voting stops, even in states where an overwhelming landslide is assumed or underway. The idea is Heisenbergian; an early announcement shouldn’t be allowed to affect the turnout or decisions of late voters. Apparently, for MSNBC and the AP, the same logic applies to a speculative call made on the basis of demographics and pre-vote polls.

I agree that calling the race before the polls closed would have been unseemly. On the same page, calling it without a drop of voting day data is a bad idea. But MSNBC’s decision is worth thinking about for another reason. It ratifies the clear, but uncomfortable and sometimes-avoided, Heisenbergian truth that idle media prognostication about the race changes the race. They’d decided who was going to win. So why else, but for Heisenberg, wait to color the district Obama-blue?

Clint Hendler is the managing editor of Mother Jones, and a former deputy editor of CJR.