What to do now? Since you can’t go back in time, I would remove any support troops we have in Syria. I would let the Russians support Assad to keep control of Syria and help destroy ISIS and the Syrian Rebels. Keeping Assad in power will help keep ISIS and the Syrian Rebels in-check. You don’t want any Radical Muslims to control Syria. The only issue with keeping Assad in power is that he is friendly with Iran and I am sure Iran is already helping him even more now in Syria. Iran would love to use Syria as a stepping stone to destroy Israel, so I would give any military support in weapons to Israel so that they can protect their Northern border with Syria and Lebanon. Defeating ISIS in Syria will also benefit to protect Jordon since ISIS would love to take over Jordon by going through Syria.
How did we get in this mess?
obama and hillary supported the Arab Spring effort to remove the dictators of Libya, Egypt, and Syria. Didn’t we learn from Iran when Jimmy Carter helped to remove the Shah of Iran and then assisted in helping put in the ayatollah khomeini? The Middle East and World sure changed after that Big Mistake!