In advance of the Oct. 19 presidential debate at UNLV, The Sunday and the Brookings Institution, in partnership with UNLV and Brookings Mountain West, are presenting a series of guest columns on state and national election issues. The columns will appear weekly.

At the end of July, shortly after retired Gen. John Allen spoke at the Democratic National Convention, Gen. Martin Dempsey, retired chairman of the joint chiefs of staff, criticized Allen for his involvement in this year’s presidential race. Allen has taken the stance that Donald Trump could cause a historic crisis in civil-military relations because of Trump’s stated intention to order the military to commit illegal or immoral actions such as waterboarding and carpet bombing.

I believe Allen, with whom I oversee the Brookings Institution’s Center on 21st Century Security and Intelligence, is correct to recognize the severity of the threat Trump would pose to our military and broader foreign policy. The stakes are too high to stay silent.

While Dempsey contends that retired military personnel should, and generally do, stay out of partisan politics, there is a long history of high-ranking officers going on to hold high offices, including George Washington, Ulysses S. Grant and Dwight Eisenhower. Beyond participation through elected office, such military figures have lent perspective to our heated political process, from Gen. Colin Powell endorsing Barack Obama for president eight years ago to the former officers who defended John Kerry when the presidential candidate was denigrated in 2004 by a right-wing group for his supposed failings in uniform during the Vietnam War.

Dempsey’s rule doesn’t work in practice, nor should it, though there are some rules that should apply. Active-duty officers should not engage in political activity, nor attempt to inculcate their troops with their own views. Even retired officers should be careful about impugning the integrity of a presidential candidate based on national security secrets they do not and cannot be expected to know. As such, it was good to see Allen spend more time in his speech commending Clinton than denigrating her opponent. Former military officers should be careful about teaming up in a concerted way to back one candidate and attack another by invoking their military credentials in what amounts to intellectual bullying or political shaming. In fact, Allen’s speech was a response to attacks against Clinton that other notable Americans, including other retired military officers, had for months been carrying out. And ideally, retired officers should voice their views with a degree of restraint, and precision, avoiding sweeping arguments when it is possible to make their points in a professional and specific way.

Some of these guidelines are murky, but it’s better to debate the gray areas of public policy than to deprive our national political debate of the seasoned and reasoned views of some of its finest and most knowledgeable citizens, just because at one time they happened to wear the uniform of the American armed forces.

Some other critiques of Allen’s brilliant convention speech also do not hold water:

Hillary’s going to win anyway, so it wasn’t needed.

This kind of thinking — assuming victory before it happens — is not even sound for football coaching, much less something of such huge consequence as a presidential election. One can never sit on a lead. And in fact, when Allen gave his speech, Clinton trailed in the polls.

It would have been better for Gen. Allen to be more dispassionate.

Allen’s speech was rousing and strong, partly because the room was noisy and many Bernie Sanders supporters had shouted down former Secretary of Defense Leon Panetta earlier in the week. But Trump had been loudly belittling and mocking Clinton’s national security record for so long, and others had been joining in the claim that she has somehow been reckless with our national security (including at least one former Army general and a former speaker of the House), that credible and passionate support of Clinton was needed. The stakes warrant the full range of human emotion.

Allen ignored civilian control of the military.

He was out of uniform. The situation was not comparable to McClellan in the Civil War or MacArthur during World War II and the Korean War. Allen’s decision to engage in the political debate is more reminiscent of Washington, Grant and Eisenhower, with maybe a little bit of Colin Powell thrown in, than some firebrand general or active-duty military leader verging on insubordination.

The stakes weren’t high enough to warrant such behavior.

Trump calls for carpet bombing, casual thinking on nuclear weapons, torturing prisoners and abandoning allies we are treaty-bound to protect. I cannot imagine much higher stakes.

Recently, the esteemed retired Gen. Barry McCaffrey explained why his opposition to a Trump presidency means he supports Clinton. It is, after all, zero-sum time in this year’s race; one can construct fantastical scenarios about third-party candidates or late entries, but our next president will almost surely be Trump or Clinton. Many hope this is not the case, but it is reality. I admire Allen and McCaffrey for recognizing as much, and hope others will join them.

A career intelligence officer and former acting head of the CIA, Mike Morrell, also supports Clinton for similar reasons. And Aug. 8, a group of some 50 top national security Republicans, including retired four-star Gen. Michael Hayden, explained why they would not support Trump.

Allen, and now McCaffrey, have displayed a kind of wisdom and moral courage that some of their peers are counseling them against expressing in public. Allen and McCaffrey are serving their country in a crucial way at a perilous time. They have every right to do so, and the nation needs them to do so.