Secretary of State John Kerry’s testimony on Tuesday served to remind us how a single presidential decision can have monumental effects. For the president who said a decade of war was ending, the decision not to act in a bloody war in which WMD’s had been repeatedly used was the tipping point in an already floundering foreign policy. The contrast with his predecessor is stark.

FILE - In this Thursday, Nov. 27, 2003 file photo, U.S. President George W. Bush carries a platter of turkey and fixings as he visits U.S. troops for Thanksgiving in Baghdad. Anja Niedringhaus, a courageous and immensely talented Associated Press photographer who has covered everything from sports to war, was killed while covering elections in Afghanistan on Friday April 4, 2014. Niedringhaus was in a car in eastern Afghanistan with AP reporter Kathy Gannon when, according to a freelancer who was with them, an Afghan policeman approached them, yelled "Allahu Akbar" - God is Great -and opened fire on them in the back seat with his AK-47. Niedringhaus was killed instantly and Gannon was wounded. (AP Photo/Anja Niedringhaus, File)
President Bush carries a platter of turkey and fixings as he visits U.S. troops for Thanksgiving on Nov. 27, 2003, in Baghdad. (Anja Niedringhaus/Associated Press)

George W. Bush’s arguably finest moment as president and President Obama’s worst moment involved a similar dilemma: When does the commander in chief put country above politics and lead on foreign policy despite the adverse political consequences? When the chips were really down, Bush championed the surge in Iraq; when the chips were down in Syria for violation of the red line, Obama blinked.

Bush went outside the chain of command to find experts and a general to devise a new strategy when he saw the war strategy wasn’t going well. Obama hid behind obvious catastrophizing by the military when he decided to avoid holding to his red line.

Bush took full responsibility for the strategy. Obama claimed it wasn’t “his red line,” but Congress’s and the international community’s.

Bush knew it would cost him politically and his party the House. (It did.) Obama saw the results of the vote in the British parliament and ran for cover. He punted the decision at the last moment to Congress to provide him with a vote on authorization for use of force.

On January 10, 2007, Bush gave a speech to the country explaining what was at stake: “The situation in Iraq is unacceptable to the American people, and it is unacceptable to me. Our troops in Iraq have fought bravely. They have done everything we have asked them to do. Where mistakes have been made, the responsibility rests with me. . . .This will require increasing American force levels. So I have committed more than 20,000 additional American troops to Iraq. The vast majority of them — five brigades — will be deployed to Baghdad. These troops will work alongside Iraqi units and be embedded in their formations.” He went on to explain the elements of the strategy and why he thought it would succeed. (It did.)

Obama went before the American people in September, 2013 and gave a speech so internally contradictory and unconvincing that rare consensus formed across party lines that this was a disaster.

Bush was able to hand off a military success to Obama (who promptly dropped the ball by not concluding a security of forces agreement). Obama’s decision not to act arguably will have ripples for years to come — a prolonged Syrian civil war with thousands more dead, an emboldened Iran, the revival of Russia as a Middle East power, encouragement to Vladimir Putin that aggression (e.g. Ukraine) would not be met with U.S. force.

Bush’s conduct of the war is hardly beyond criticism. From the flawed intelligence on WMD’s to the years of drift before the surge, Bush bears ultimate responsibility. But when it mattered most he got it right, going against his party, the media and the polls. Obama’s Syria policy, if you can call it that, has been a disaster from the get go. When given the opportunity to course correct, Obama blinked and succumbed to his base and popular opinion. If you want to know the difference between the presidents there’s no better example than this.

Jennifer Rubin writes the Right Turn blog for The Post, offering reported opinion from a conservative perspective.