If President Barack Obama wants to begin reversing his “irredeemably weak” stature in the Middle East, he has to respond forcefully — that, is militarily — to Syria’s use of chemical warfare against its own population.

“Irredeemably weak” is the label applied to Obama by a well-wisher, foreign policy expert Walter Russell Mead, in a brilliant analysis last weekend in The Wall Street Journal of the president’s multiple miscalculations in the region, titled “The Failed Grand Strategy in the Middle East.”

According to Mead, a professor at Bard College and editor of American Interests, Obama (1) thought moderate Islamists could govern well and democratically in Egypt and Turkey, (2) systematically offended strategic allies like Israel, Saudi Arabia and Egypt’s military, (3) thought killing Osama Bin Laden and drone-bombing terrorists targets would contain jihadism and (4) failed to understand how costly it would be to avoid intervening in Syria’s civil war.

“The failure to intervene early in Syria … has handed important victories both to the terrorists and the Russia-Iran axis, and has seriously eroded the Obama administration’s standing with important allies,” Mead writes.

“Russia and Iran backed Bashar al-Assad; the president called for his overthrow — and failed to achieve it … So, President Vladimir Putin and Supreme Leader Ayatollah Ali Khameni now believe they are dealing with a dithering and indecisive American president — and are calibrating their policies accordingly.”

Mead calls for “a much tougher policy on Syria” but doesn’t exactly call for what seems absolutely necessary — bombing out at least Assad’s capacity for waging chemical warfare and, possibly, establishing a no-fly zone so Assad’s planes are grounded.

A year ago, Obama said that use of chemical weapons was a “red line” that Assad wouldn’t be allowed to cross.  He’s crossed it, killing thousands. If Obama does not act now — and he can doubtless get allies to help — it will further embolden the entire Russian-Iranian axis, which includes Hezbollah in Lebanon.

If he does act, it may restore a measure of confidence in the allied nations terrified of Iranian expansionism — especially Saudi Arabia and Israel — and those being destabilized by the civil war, especially Jordan, Lebanon and Turkey.

Ever since evidence on chemical attacks began pouring in last week — and ghastly pictures of dead victims, including babies — the Obama administration has been making noises about “considering options,” including military. The longer the dithering goes on, the weaker he looks.

Obama clearly did not — and does not — want to be a “war president.” His highest foreign policy priority was to get out of Iraq, which is now tilting toward Iran. Next was to “surge” in Afghanistan — then get out, which is likely to lead to a Taliban takeover of much of the country. He killed bin Laden, but staying out of Syria has made it a training ground for terrorists.

And, meanwhile, Iran continues working on nuclear weapons, Obama’s sanctions notwithstanding.

Obama’s efforts to avoid war are an object lesson in how a war-avoidance strategy can make war inevitable. Syria is a necessary place to reverse course.