Minutes after President Barack Obama concluded his strong and sensible address explaining how he intends to destroy the terrorist organization the Islamic State, Republicans popped up on television like political snipers. He should have kept a "residual force" in Iraq, complained Sen. John McCain, R-Ariz., and he is to blame for the Islamic State's advances. He sounds just like George W. Bush, gloated former House Speaker Newt Gingrich, and he is reluctantly enacting the advice of Dick Cheney.

None of those remarks was accurate, but the falsehoods revealed once more the irrepressible Republican impulse to slur a Democratic president — even when the nation faces a serious security threat. In this instance, as the president attempts to unite us and bring together a broad coalition of allies, their behavior is worse than inappropriate. Indeed, were the roles reversed, the Republicans would surely describe such conduct as unpatriotic.

When the roles actually were reversed, as the anniversary of 9/11 might remind us, Democrats rallied immediately behind President Bush and his plan to attack the Taliban and al-Qaida. Even while Republicans scurried to lay blame on former President Bill Clinton, the loyal Democratic opposition stifled obvious questions about why the Bush White House had done so little to thwart those who had just attacked the World Trade Center and the Pentagon. As American troops went into Afghanistan, those questions would, years later, await the 9/11 Commission (which Bush and Cheney furtively attempted to derail).

Dissent is always to be valued and protected in America, but the instant Republican attacks on Obama's speech scarcely qualify as principled criticism. After all, the president is already hitting the Islamic State with airstrikes, as most Americans now believe he must, and has vowed to extirpate that barbaric and blasphemous gang. Unless the Republicans want to urge a wholesale reinvasion of Iraq — which they know would be politically suicidal — there isn't much for them to dispute in the president's announced strategy.

Substantive debate over tactics and strategy isn't what Republicans want anymore. Rather than contribute constructively to the policy process, they blather on and on about mistakes and gaffes that can be marked against the president. Some of those alleged errors, such as his decision against arming the Syrian opposition, are matters for serious argument. Others — such as McCain's contention that we should have left a "residual force" in Iraq, preventing the rise of the Islamic State — are not.

As noted here months ago — when the Arizona Republican made the same claim — both the Iraqi government and the American public clearly wanted U.S. troops out of that country. Nouri al-Maliki, the divisive Shiite sectarian then leading Iraq, refused to provide legal immunity to U.S. troops. That triggered the status of forces agreement signed by President Bush in December 2008, which required a complete withdrawal by Jan. 1, 2012.

Would a remnant force of U.S. troops have stopped the rise of a new Sunni insurgency, led by jihadi, under the divisive al-Maliki regime? That seems a doubtful assertion, no matter how often or how angrily McCain says so. What seems considerably less arguable, however, is a simpler thesis: Without the invasion of Iraq, the Islamic State would never have been spawned.

The neoconservatives who promoted that ruinous adventure have loftily advised us all not to reargue the decision to overthrow Saddam Hussein and occupy Iraq. Their desire to avoid accountability for a historic blunder — still costing so many lives and so much treasure — is understandable, if not quite honorable. But if they want amnesty for themselves, they might stop trying to frame President Obama for the awful consequences of their misconduct.