In my opinion, there are not any oxymorons in contemporary politics, at least not on the level of "War is Peace." Any politician who used anything that blatant would become a laughingstock.
I can think of at least a few things that would be called oxymorons by their opponents. Democrats didn't think much of the idea of "compassionate conservatism" back when Pres. Bush used it at the beginning of this decade.
But mostly, I think that modern politicians use euphemisms way more than anything that could be an oxymoron. Just about any term we use these days is a euphemism...
That is a great request. Like you intimate some people state that the best way to advocate for peace is to prepare for war. The best one that I recently heard is the idea that you need to spend to get out a recession! Create more deficit to stimulate the economy. It might be true, but who knows?
Here is another one - "cash for clunkers."
It was not a political event, but it's become political: The shooting at Ft. Hood was a terrorist act.
The shooting at Ft. Hood is an example of a soldier in trouble.
Both statements are true,in the minds of those who spoke them; therefore, the situation itself is/was oxymoronic.
The current controversy about the NYC Terrorist Trial is a similar situation, and so is all the hooey (IMHO) about the Health Care Bill and about the war in Afghanistan.