WASHINGTON — For all the armchair generals advocating U.S. military intervention in Syria, I have a few questions:

Is human suffering the reason for the United States to act? That is the noblest and most altruistic of motives, and the estimated 70,000 lives that have been lost in Syria constitute a tragedy. But is there a numerical benchmark that constitutes a trigger for intervention?

Didn’t genocide in Rwanda claim hundreds of thousands of lives? Didn’t war in the Congo kill an estimated 3 million? Should we have intervened in those conflicts? Should it be U.S. policy to act whenever the toll of death and destruction in any civil war around the world reaches some critical point? Or should we send in the military only when we can see the horror on television?

Is the fact that Bashar al-Assad possesses chemical weapons — and may have used them — the reason to intervene? President Obama called this a “red line” that must not be crossed, and now critics are pressing him to back up his words. But what do we really know?

Would the intelligence analysts who agree that chemical weapons have been used in Syria be the same intelligence analysts who agreed 10 years ago that Saddam Hussein had weapons of mass destruction? Isn’t it true that Saddam, as it turned out, apparently didn’t even have an active program to obtain WMD?

Didn’t we learn in Iraq that despite consensus among officials and commentators about a rogue nation’s secret WMD capabilities — with the CIA director calling the evidence a “slam dunk” and the national security adviser raising the specter of mushroom clouds — it’s possible that the consensus is wrong?

If chemical weapons indeed were used, are we certain who used them? U.S. officials believe it was Assad; a United Nations official has suggested it might have been the rebels. Shouldn’t we be certain where, when, how and by whom chemical warfare was practiced? We know that Assad is a monster, but don’t we need to firmly establish blame before meting out punishment?

Is it Syria’s strategic location in the Middle East that makes it necessary for the United States to intervene? Are we worried that continued chaos there would sow instability across the region? If this is our fear, what makes us think that U.S. military intervention would make things better?

Wouldn’t the measures being talked about — missile strikes to cripple Assad’s air force, establishment of a no-fly zone, giving the rebels heavy weapons — tend to make the situation more chaotic rather than less, at least in the short term? Can we be sure that this sort of campaign would push Assad’s thuggish regime to its tipping point? If it didn’t, then what?

If Assad somehow managed to hang on, controlling some parts of Syrian territory while various groups of rebels controlled the rest, wouldn’t the country be in danger of breaking apart? As fighting continued and the refugee crisis worsened in neighboring Jordan, Turkey and Iraq, wouldn’t these U.S. allies be justified in pressing for American boots on the ground in Syria to stabilize the situation?

If the Assad government did fall, who would take over? From all reports, jihadist rebel factions are the best organized and most capable. Do those who cite Assad’s stocks of chemical weapons as a reason to intervene want to see them inherited by al-Qaida’s ideological brethren? To ensure that the chemical weapons were destroyed or that they were controlled by more moderate, pro-Western factions, wouldn’t more than words be required? Wouldn’t we have to maintain a troop presence?

Doesn’t the “Pottery Barn rule” — you break it, you own it — still apply? We still “own” Afghanistan, where the CIA regularly delivers bundles of cash to a corrupt government and the biggest danger to U.S. forces is from our ostensible allies. In a sense, we still “own” Iraq, where sectarian violence is again threatening to spin out of control. If we intervene in Syria, won’t we “own” that country as well?

Isn’t it the case that Syria presents no good options, only bad ones? Isn’t it unclear whether U.S. intervention can even alleviate the Syrian people’s pain, much less advance U.S. interests? And although doing nothing seems like a bad alternative, doesn’t the only other choice presently available — doing something for the sake of doing something — look worse?

Last question: We have been at war in Afghanistan for a dozen years and in Iraq for a decade. Have we learned nothing at all?

Eugene Robinson is a Washington Post columnist. His email address is eugenerobinson@washpost.com.