Can a president speak out forcefully in favor of an opposition cheated in an election without inflaming a nationalist reaction? Well, President Clinton did it. Four days after Milosevic stole an election in September 2000 — in a country we had just bombed — Clinton issued this statement:

The people of Yugoslavia have spoken loud and clear in support of democratic change.
The opposition’s claims to an absolute majority are backed up by certified results from the polling places. The government’s commission acted in secret and excluded the opposition. One of its top officials has resigned. The Serb Orthodox Church has recognized Mr. Kostunica as Yugoslavia’s new president.
It is time for Mr. Milosevic to heed the call of the Serb people, step down, and allow a peaceful democratic transition to take place.
We have said before that as soon as a democratic government is in place, we will immediately take steps to remove economic sanctions and help Serbia with its transition.

Now, of course, all the usual caveats apply about the different circumstances in the two situations. But it’s still a stark contrast with Obama, and, of course, Milosevic did indeed fall. A timeline here.