It is always difficult when listening to the public statements of political leaders to know how much of their rhetoric they actually believe. It is always a very safe assumption that there are various political and policy concerns influencing their positions that are left unstated. This is the situation that we find ourselves in when considering the current push for military intervention in Syria.
There are numerous issues involved. There is the accuracy of the intelligence being used to justify an intervention. The shadow of Iraq and the WMDs hangs over this discussion. The advocates of intervention attempt to reduce that complex problem to saying that Bush lied and that Obama is telling the truth. Neither of those statements can be proved beyond reasonable doubt. The intelligence that Powell presented at the UNSC as a justification of threat turned out to be wrong. Saddam had had such weapons at one point. He used them on the Iranians and on the Kurds. The present on the ground realities may turn out to be different, but the past experience provides reason for skepticism.
However, a more useful comparison between the two situations is the issue of outcomes from an intervention. There is a recurring belief among various perspectives in US political circles that the US can and should use its hegemonic power to intervene in the affairs of "failed states" and turn them into stable and prosperous democracies. The proponents of this argument have to reach back to WWII and the outcomes for West Germany and Japan following an extended US occupation. There are all sorts of reasons why this analogy doesn't work in the Middle East. I'm not going to try to rehash them here.
Iraq was the place where the US used pretty much everything it had to try to fix the place. With the control of a full military occupation there was an all out effort to lead them by the hand to the fullness of a secular democracy. It simply didn't work. After billions of dollars and the lives of many people. the US pulled out in frustration and failure. The warring religious/ethnic factions are still bombing each other. Americans are now doing their best to ignore the mess, but I don't hear anybody claiming that the effort was a success.
Our more recent intervention in Libya hasn't worked out particularly well. The staged political outrage over the Bengazi incident has pretty much obscured the rest of post-Qaddafi reality. The people who have put together the recognized government have control over only part of the country. The situation is decidedly unstable and people would likely qualify as terrorists have been scattered over large areas of Africa.
The various movements of the Arab "Spring" have not lived up to the initial promise of bringing a magical transformation of the region. Egypt is perhaps the most visible case. The military is back in control and there is blood in the streets.
One of the underlying problems in much of the region is that the entities that are presently recognized as nation states were creations of various colonial administrations that drew arbitrary lines combining ethnic groups that had absolutely no affinity for working cooperatively with each other. At a regional level there are similar conflicts between states. Saudi Arabia and Iran are sworn enemies and everybody hates Israel.
So now Obama and his chief salesman Kerry are proposing to climb on their white horses and ride into battle as champions of humanitarian intervention. The plans and objectives of their undertaking keep shifting. Initially it was just going to be an offshore missile attack to punish Assad for using nerve gas. Now there is an essential acknowledgement that the goal is regime change with the claim that this can be accomplished without boots on the ground. We are supposedly going to send in advisers to train one faction of the rabble of rebels. This brings back memories of Vietnam.
There is really nothing in the experience of dealing with the nations of the Middle East to give any confidence that what Obama says he wants to accomplish in Syria can be achieved by Obama or anybody else. There are some other goals that Kerry has mentioned like intimidating Iran and Russia which are also likely part of the plan. Those might be accomplished in the short term, but it seems highly unlikely that matters will be improved in Syria anymore than they were in Iraq.