You got your history wrong.Funny thing though, when war erupted in 1939, the Kingdom of Romania was considered pro-British and had an alliance with the Poles. A lot of the problems Romania had at the time where staving off attacks and annexations of its regions from the Germans and the Soviet Union. Then Romania got itself into bed with the Germans and joined the effort to try to invade other countries or, in some cases, taking back land that was theirs to begin with. It wasn't until Romania, along with Germany, having conquered territory in Russia some time later, and then having met with major losses in Stalingrad, that Romania started to secretly negotiate peace with the Allies. Romania was apparently switching sides between the Germans, Russia, and the Allies. In fact, Romania and the US have been allies and strong supporters of each other for decades. You need to get your facts straight.
Firstly, Romania was more or less forced to give up territory, and later control of the country to pro-Soviet interests following the Treaty of Munich, as Romania realized England/France wouldn't protect it.
In that respects, it's no surprise that Romania made it bed with the Nazi's, given how the Allies gave it up and the Soviets took a large swath of it's territory. The Allies gave it up a second time after Yalta Conference, in order to maintain Soviet support.
So Romania did not "switch sides", it was outright abandoned by the Allies, invaded by the Soviets, and after the Germans were pushed back out of EE, surrendered to the Soviets and became a satellite state following Allied concessions at Yalta. What you are pushing is a bias American point of view that totally distorts history to make EE look like the bad guys.