American are not in favor of striking Syria, unlike past wars where the support has been higher. 
Tuesday night President Obama faces an American public more skeptical about taking military action than ever before. According to a recent NBC News/Wall Street Journal poll, 58% want Congress to vote no on Syria. When we invaded Iraq and Afghanistan, American support was much higher. According to Gallup, 59% were in support of Iraq and 82% were in support of Afghanistan. Even our invasion of Kosovo had greater public support as 43% of Americans were behind the attack. Regardless of Americans support going into conflict, history shows it usually disappears within the first month of the strikes.
During President Obama’s presidential address Tuesday night he needs “to talk very directly about his real reasons for wanting to possibly have the strike.” NBC News historian Michael Beschloss said on Tuesday’s show. “One of the best things he can do is to say ‘before you Americans support this you should know that it’s entirely possible that such and such could happen and may last a long time.’”