Ok, so basically, King Carol II of Romania had used much of the 30's to sabotage all of the democratic parties and subverted democracy to the point where he and his movement where the only legitimate political force. Any opposition was either subjugated (the democratic parties) or violently purged (the fascist Iron Guard).
OTL, this did him no good in the end since the Soviet Union, Hungary and Bulgaria took for themselves bit and pieces of the country, and his popularity plummeted. The military and the fascists took over after he abdicated, with the military under Antonescu eventually getting rid of the the nazi look-alike's of Horia Sima.
But, what if he decided opposing foreign aggression was the only way to save himself ?
Specifically, he tells Hitler (as convincingly as possible) that if he continue's to push for Hungary to get a slice of Transilvania, Romania will fight. And not only that, it'll keep fighting till the bitter end, and also blow up all the oil refineries and oil extraction facilities.
However, if he (Hitler) backs off and tells Hungary and Bulgaria to do the same, he can have all the oil he wants in return for bits of technology and discounted prices.
Would this bluff work ? Would Hitler risk attacking Romania, because, if he does and the oil rigs go up in flames, it'll be years before production is back up again, meaning no Barbarossa?
What butterflies can we expect if Hitler doesn't call Carol's bluff and respects Romania's neutrality in return for oil ?