We can pay the interest just fine. The dollar, however weakened, is still the world's reserve currency. Our economy, however bad it gets, and our Treasury securities are still looked up to as the safest place to park funds. How much is too much debt? Ask Japan, this can go on for decades, as long as we can print, we haven't reached the limit. Congress is responsible for fiscal policy, but they can't restrain spending, so the Fed handles it thru monetary policy. No different than Europe, Japan, etc.
Regarding Syria, it was always about a Nat gas pipeline thru Syria. The pipeline is good for Saudia Arabia and bad for Russia. Russia avoided the war by taking away the motive. The rest of the World doesn't see us as chicken for letting Russia keep Syria in line. In fact, the rest of the World thought we were wrong to help Suadia Arabia get a pipeline. That's surely not over, but Russia has economic reasons to keep us out of Syria, and Saudia Arabia has economic reasons to bring us in. Time will tell, but don't kid yourself that it has anything to do with our strength or weakness. Money talks and BS walks.
