It is much, much easier to measure weakness, smallness and failure. And in the case of President Donald Trump, we can tragically measure his failure in American lives lost during this pandemic. The cost of Trump's pathological insecurity, his overweening ego and his rank incompetence is a failure to provide the national leadership that could have prevented at least some of the roughly 140,000 Covid-19 deaths in the US.

That's because it took that many people — and months of talk — for the President to finally, publicly and unequivocally promote the lifesaving practice of wearing a mask in public places.

Monday night he tweeted — as if he'd just heard about the idea over golf — and seemingly without any irony: "We are United in our effort to defeat the Invisible China Virus, and many people say that it is Patriotic to wear a face mask when you can't socially distance. There is nobody more Patriotic than me, your favorite President!" The black-and-white photo accompanying the tweet showed Trump wearing a face mask with the presidential seal in the corner.

Setting aside the myriad polls that show he certainly is not our favorite President — not by a long shot — this is a bandwagon we all wish he'd hopped on much, much sooner.

Instead, we watched him constantly and petulantly resist doctors' orders — even his own — to wear a mask in public, refusing while touring businesses big and small, while holding press conferences, while meeting veterans, while speaking to hundreds of people at his rallies.

He spent months feigning a kind of macho ambivalence toward masks, saying at one time, "this is voluntary — I don't think I'm going to be doing it." He bizarrely insisted he was refusing to wear one in public simply to stick it to the media: "I wore one in this back area but I didn't want to give the press the pleasure of seeing it," he said after touring a Ford plant in Michigan. Risking your life to "own" the press is a weird flex.

He even went so far as to discourage mask-wearing, calling them "double-edged swords" and mocking former Vice President Joe Biden for wearing one, because real men get their friends, family and co-workers sick, I suppose.

Now, suddenly, Trump is suggesting that wearing a mask means caring about the country — something Biden, Democrats and most congressional Republicans have known for months.

Of course, Trump could still walk it back. He wore a mask for the first time in public when he visited ailing service members at the Walter Reed hospital earlier this month, but rejected the idea of a national mandate for masks in an interview with Fox News' Chris Wallace that aired Sunday. "I don't agree with the statement that if everybody wore a mask, everything disappears," Trump said.

Still, as lame and late as Trump's attempt at lifting his standing in the polls is, Monday's tweet and the gesture are much more than just empty symbolism.

What Trump says, his most loyal supporters will do, no matter how impolitic, deleterious or deranged, as