Even if the President musters enough votes to strike Syria, at what political cost? Any president has a limited amount of political capital to mobilize support for his agenda, in Congress and, more fundamentally, with the American people. This is especially true of a president in his second term of office. Which makes President Obama’s campaign to strike Syria all the more mystifying.

President Obama’s domestic agenda is already precarious: implementing the Affordable Care Act, ensuring the Dodd-Frank Act adequately constrains Wall Street, raising the minimum wage, saving Social Security and Medicare from the Republican right as well as deficit hawks in the Democratic Party, ending the sequester and reviving programs critical to America’s poor, rebuilding the nation’s infrastructure, and, above all, crafting a strong recovery.

Time and again we have seen domestic agendas succumb to military adventures abroad – both because the military-industrial-congressional complex drains money that might otherwise be used for domestic goals, and because the public’s attention is diverted from urgent problems at home to exigencies elsewhere around the globe.

It would be one thing if a strike on Syria was critical to America’s future, or even the future of the Middle East. But it is not. In fact, a strike on Syria may well cause more havoc in that tinder-box region of the world by unleashing still more hatred for America, the West, and for Israel, and more recruits to terrorism. Strikes are never surgical; civilians are inevitably killed. Moreover, the anti-Assad forces have shown themselves to be every bit as ruthless as Assad, with closer ties to terrorist networks.

Using chemical weapons against one’s own innocent civilians is a crime against humanity, to be sure, but the United States cannot be the world’s only policeman. The UN Security Council won’t support us, we can’t muster NATO, Great Britain and Germany will not join us. Dictatorial regimes are doing horrendous things to their people in many places around the world. It would be folly for us to believe we could stop it all.

Obama and his secretary of state, John Kerry, are now arguing that a failure to act against Syria will embolden enemies of Israel like Iran and Hezbollah, and send a signal to Iran that the United States would tolerate the fielding of a nuclear device. This is almost the same sort of specious argument – America’s credibility at stake, and if we don’t act we embolden our enemies and the enemies of our allies – used by George W. Bush to justify toppling Saddam Hussein, and, decades before that, by Lyndon Johnson to justify a tragic war in Vietnam.

It has proven to be a slippery slope: Once we take military action, any subsequent failure to follow up or prevent gains by the other side is seen as an even larger sign of our weakness, further emboldening our enemies.

Hopefully, Congress will see the wisdom of averting this slope.