The Associated Press, the nation’s leading and most respected wire service, has always erred on the side of caution. Buried deep in the AP’s DNA is the hazy memory that its leading competitor, the United Press, stained its credibility for decades by prematurely announcing the end of World War I.

But never in the following century did the Associated Press write anything this blunt about any American elected leader: “President Donald Trump can’t be counted on to give accurate information to Americans when violent acts are unfolding abroad.”

That lede on a Monday “AP Fact Check” article by Calvin Woodward and Jim Drinkard actually understated the president’s duplicitous fearmongering in response to Saturday night’s terrorist attack in London.

Take the most vicious presidential statement on Saturday night delivered through Twitter: “At least 7 dead and 48 wounded in terror attack and Mayor of London says there is ‘no need to be alarmed!’” Trump’s snide tweet about London Mayor Sadiq Khan took his remarks wildly out of context (he was referring to the massive police deployment as nonalarming).

But more than that, who in his right mind attacks the mayor of a city that has just been hit by a terrorist attack? Imagine if British Prime Minister Tony Blair’s first instinct after the Twin Towers toppled on 9/11 was to ridicule New York City Mayor Rudy Giuliani.

And rather than feeling embarrassed about his intemperate comments, Trump return to the fray Monday morning as he sent off another unhinged tweet attacking Khan for his “pathetic excuse.”

And tune out reality?

Trump, whose lack of curiosity is only exceeded by his arrogance, cannot even muster the focus to attack first and ask questions later. Instead, the only question that, I suspect, Trump ever asks in a crisis is “Can you make the sound on Fox News louder?”

The sad thing is that Trump’s snarling reaction to the London attacks is typical behavior for a president who is tireless in his efforts to invent and inflame terrorist attacks.

Announcing America’s withdrawal from the Paris agreement on climate change Thursday, Trump dramatically declared, “I would like to begin by addressing the terrorist attack in Manila.” There was only one problem: The fire in a Manila casino that Trump referred to was apparently a botched robbery attempt — and not terrorism.

Yes, it is an ugly world where citizens of our closest ally (at least before Trump) cannot attend a concert in Manchester or walk across a historic bridge in London without fearing for their lives. But it is hard to see how Trump’s outbursts contribute to a prudent strategy on how to contain and limit terrorism.

Nothing is more important in a crisis than presidential credibility. But, as the Associated Press underscored, how can you trust any syllable uttered by the president? Trump brings to mind the famous Mary McCarthy attack on Lillian Hellman: “Every word she writes is a lie, including ‘and’ and ‘the.’”

Stepping up

All this suggests that Congress — which often forgets that it is a coequal branch of government — needs to be far more assertive in national security matters. Before America faces the almost inevitable next terrorist incident, the nation needs a bipartisan series of high-profile hearings on what should be an appropriate and measured response.

Of course, it is difficult to discuss anything in Congress without both parties trying to score political points. Even the weather (once the most bland topic of human conversation) has become a flashpoint for bitter arguments over global warming.

What this weekend should have demonstrated — even for loyal Republicans skeptical of media attacks on Trump — is that the president cannot be trusted in a crisis.

What we are dealing with here are not the necessary, but often decried, stories of White House dysfunction based on anonymous sources. This time around, the evidence of Trump’s unreliability is evident in the words that he chose to share with the world through Twitter.

All this is not a prelude to a predictable liberal fantasy about impeachment or the temporary removal of the president under the unwieldy mechanisms of the 25th Amendment.

Donald Trump is the duly elected president of the United States — and nothing we know so far warrants even contemplating his removal. But being legitimate is a far cry from deserving automatic deference from either Republicans or Democrats in Congress.

It is an admittedly murky situation.

But, in a crisis, there are areas where Congress has the right — and the obligation — to seize a lead role. If the White House has chosen to traffic in hyperbole and mendacity, then Congress must be the repository of truth. In the case of a terrorist incident, Congress, using its powers of subpoena, must promptly and reliably inform the American people what has occurred and what appears to be behind it.

The other challenge facing Congress is how to avoid being stampeded into passing draconian legislation in the wake of a terrorist incident. The fear of being labeled “soft on terrorism” can silence the skepticism of members of both parties.

This is an arena where civil-liberties Democrats and libertarian Republicans can find common ground. Normally, in a crisis, Congress bows before the legislative wish list from the executive branch. But, for as long as Trump remains president, Congress must assert its independent judgment.

The time for illusions about the nature of a Trump presidency has long passed. That’s why those of us who cling to hope about America’s future desperately look to, yes, a Republican Congress to rouse itself from its willful slumber. For patriotism requires more than dreaming of tax cuts while serving as Trump’s enablers.

Roll Call columnist Walter Shapiro is a veteran of Politics Daily, USA Today, Time, Newsweek and The Washington Post. Follow him on Twitter @MrWalterShapiro.