The idea that American presidents must basically go into occultation, focus on memoir-writing, or transform themselves into nonpartisan cheerleaders for various uncontroversial causes is deeply engrained in American culture. From George Washington retiring back to his plantation to Harry Truman and Lyndon Johnson basically disappearing from the public eye altogether to George W. Bush becoming a quietly reflective painter, few ex-presidents have remained active in the country's political life after leaving office. Citizens don't generally want someone who dominated public debates for four or eight years interfering with the workings of a new administration, one that typically enters office with a temporary surfeit of goodwill and popularity that crosses party lines. Even popular presidents have typically worn out their welcome by the time they leave.

In normal times, this makes a certain kind of sense. New presidents should, ideally, be granted time to fulfill their campaign promises and enact sensible public policy without the last president hovering over their shoulders like latte-addled helicopter parents. And even presidents who left office ostracized and alone have, over time, gradually become unifying figures, in part because they are free to pursue hobbies or endeavors that are not related to divisive party politics. With their high-minded departure from the boxing ring of politics, they communicate to the public that our differences are not so profound after all. This is to say nothing of the total exhaustion most presidents feel after serving one or two terms in office.

Their unique stature in American public life gives ex-presidents the power to successfully pursue transformative projects, like Bill Clinton's efforts to combat poverty with the Clinton Global Initiative, or Jimmy Carter's long and selfless efforts to build housing for the homeless. Their good works often restore the popularity they lost as president. Jimmy Carter suffered one of the worst landslide defeats in presidential history to Ronald Reagan in 1980, yet in 2011 a whopping 69 percent of Americans looked at him positively.

When George W. Bush left office in 2009, his Gallup approval rating was just 34 percent. Yet the day he left office, his popularity began a long migration upward. Today, 59 percent of Americans express a favorable view of America's 43rd president, something that was completely unthinkable when he handed the steaming ruin of America's future over to Barack Obama. Apparently, people really dig this new quiet W. If you don't think too hard about the generational wreckage he inflicted on this country, you might just like him too.

So yes, in normal times, with normal presidents, this tradition makes sense. But these are not normal times. And Donald Trump is not a normal president.

Trump is busy shredding just about every important norm of American politics — both formal rules restraining executive power and unspoken norms that guide presidential behavior. The president has also made a point of threatening his vanquished general election opponent, impugning the integrity of federal judges, and encouraging law enforcement officers to assault citizens. He continues to publicly trash the outgoing administration of Barack Obama, something that isn't illegal but that is profoundly troubling. When the president wiped away the crimes of the sadistic lawbreaker Joe Arpaio, he upended a long tradition of the president waiting years to issue his first pardon. His outrageous behavior suggests strongly that once he is out of office, he is going to go right back to making obscene attacks on the next Democratic president, using his Twitter account as a cudgel to turn the public against its leaders.

That's why the relative silence of America's five surviving ex-presidents is so deafening. While Barack Obama has released the occasional statement critical of particular policies, he has not, so far, shown any willingness to directly attack the Trump administration's multiple-front war on American democracy and decency. And while the Bushes reportedly are horrified by this presidency, they have thus far refrained from making their displeasure clearly known to the people.

That needs to change.

It is precisely the high standing of former presidents that should lead them to get off the sidelines and into the fight. The Bushes in particular are highly regarded by Republicans, the very people who need to turn on President Trump if he is to be fully isolated politically. It might be difficult to fight their way through the thick Breitbartian jungle of informational obfuscation and racist fervor, but if anyone can do it, it is former presidents who once won the votes and admiration of such people. And while they would probably prefer to spend their final years on Earth relaxing and basking in public adoration, the truth is that we need them now.

There is no law against former presidents joining forces to demand that President Trump release his taxes, to condemn his lawless obstruction of justice in the Russia investigation, and to publicly criticize the administration's cruel efforts to disenfranchise voters and deport millions of aspiring Americans. And if the president and his minions in Congress have proven anything, it is that if there isn't a law against something, it can be done. Someone like George W. Bush repudiating Trump's reckless withdrawal from the Paris Agreement would have a real impact on the public debate. George H.W. Bush issuing a public statement impugning Trump's dangerous handling of the North Korea crisis could likewise break through the closed hearts of Trump's base and alert them to the gathering danger of foolhardy statesmanship.

For Obama's part, he surely does not want to capture a share of the spotlight that needs to go to emerging Democratic leaders in Congress and governor's mansions across the country. But there is no reason for him not to make his displeasure with this administration's policies known, much more often and in much sharper terms. Obama has his car sitting at the crest of the High Road. He needs to get in and drive it back down into the scrum. Restoring the legitimacy of those norms is going to be critical both in holding Trump accountable and in ensuring that the next president voluntarily observes rules that are currently being broken without any consequence whatsoever.

Ideally, all five living ex-presidents would join forces to criticize the president's abuses of power. But Carter and George H.W. Bush are both elderly and in poor health. We can't necessarily expect too much from them. Bill Clinton, George W. Bush, and Barack Obama, on the other hand, are spry and still able to travel and raise awareness of this president's crimes and misdemeanors.

The time is now. As Obama used to say, "We can't wait."