President Obama, yesterday:
“There will be consequences if people step over the line,” Obama said shortly after landing in Mexico for a summit with the leaders of Mexico and Canada, as fires burned in central Kiev. “And that includes making sure that the Ukrainian military does not step in to what should be a set of issues that can be resolved by civilians.”
Fresh fighting broke out in central Kiev on Thursday, shattering a truce declared by Ukrainian President Viktor Yanukovich, as the Russian-backed leader met European ministers demanding he compromise with pro-EU opponents. A Reuters photographer saw the bodies of 21 dead civilians in Independence Square, a few hundred meters from where the president met the EU delegation.
You might have expected the experience with Syria to warn the president off announcing this or that consequence, and warning that this or that "line" would be crossed. In the context of Syria, it was at least consistent with the precedent of Libya—a response was backed up, tentatively, by NATO countries. This Obama declaration isn't really tethered to any response.