The 2011 action in Libya was an international effort carried out under a UN authorization to protect civilians, not a unilateral move by Obama based on a fabricated rationale. There were limited airstrikes and aid to rebels, but the US did not directly take out Gaddafi or make any pretense of "running the country."

Obama deliberately went to Congress for authorization to strike the Syrian chemical program in 2013, and after it quailed from taking a vote, the strikes didn't happen.

The 2014 strikes were against ISIS, not Syrian government forces, and carried out under the existing AUMF authorization to combat Al Qaeda and its affiliates. One can argue whether ISIS qualified (even the administration at the time acknowledged it was a stretch and wanted a more clear-cut resolution from Congress), but it definitely was a major terrorist threat in the region and had been working with AQ in the past.