The Us is Trillions of dollars in dept. To fund the campain will make it even worse. If we go and attack Syria then Russia will go to war with us. Imagen funding a war. Too much money. If we go to war against Russia the Nuclear weopons shall come and EVERYONE will die. Other countries will hate the US for attacking. Americans will die for some conflic that doesn't belong to them. It's Syria's problem. Basic fact: Syrians are killing Syrians. So now we must kill Syrians to stop Syrians from Killing Syrians in Syria. Say that 5x faster.
At this point, the US is already in a lot of debt. Joining in this war could escalate the debt beyond what we have now, even while we're trying to get out of debt. On top of that, we don't want to start another world war that would cause thousands of deaths and suffering. That brings me to my final point: from what I've heard, the U.S. Citizens don't want to have to fight a war right now. We are working through a peaceful time and it is still hard, as is. A war would just escalate that difficulty.