The only real constant to be found in both European and US politics is war. A steady feature of both regions for the past 20+ years has been small, lucrative conflicts waged against countries unable to effectively defend themselves.
It doesn't seem to matter who's in office in the US — Republican/Democrat, conservative/liberal — there's a war machine constantly running. My concern is that there's a building risk that one day that war machine is going to bust apart. And when it does, the long relative peace that the US and Europe have enjoyed (even as they've visited a lot of death and destruction elsewhere) will be shattered.