All those interventions were supported by lots of Republicans too - and they didn't cost anywhere near 300 billion dollars.
In fact, the Somalia debacle was a decision by George H.W. Bush -
http://www.empereur.com/somaliaus.html
"On December 4th, 1992, exactly a month after Bush’s defeat, he announced that the US was going to deploy a member of military force to Somalia in order to create a safe environment for the humanitarian aid mission. The deployment named Operation Restore Hope began on December 9, it peaked at about 25,800 US troops joined by thousands of other nationalities."
So that was a REPUBLICAN debacle that a Democrat inherited. And I don't think Bush the elder was wrong to want to try to help people who were starving to death.
As for Haiti, I don't see how people who support the war in Iraq can claim that it was wrong to try to intervene to keep Haiti democratic. All the nation-building Bush used to oppose he's now supporting in Afghanistan and Iraq. If anything, we didn't go far enough - sending in troops alone wasn't enough. We needed to support Haitian civil society rather than just decide who was in power.
As for Yugoslavia, Clinton's approach worked. It was a basketcase until U.S. airstrikes along with a strong peace process worked.
http://www.globalterrorism101.com/ar...ugoslavia.html
The point is that the military can only be a minor part of any real effort at peace. Clinton understood that. He didn't spend more than a few billion on each intervention - keeping our money in the surplus and ending deficits.