The difference being that Europe does not need America for this war. Putin can rally EU leaders (France especially now), and lead a multi-national invasion of the Middle East. Obama can sit it out (as yet another gift to his Muslim masters), and Putin can gain even more influence in the region afterwards. Bad for the US either way, just as the both want it.
Islam been attacking the west for almost 1500 years so a little push back is entirely justified and there good money to be made pushing back. Putin knows this and he knows he needs to act quickly while the one is still in office because a president Trump not allow Russia to take all the oil for herself.