A riot police officer aims his weapon while demonstrators protest the shooting death of teenager Michael Brown, in Ferguson, Mo., in this file photo taken Aug. 13, 2014. (REUTERS/Mario Anzuoni)

A month after protesters and heavily armed police first began to clash in Ferguson, Mo., the Senate Homeland Security and Governmental Affairs Committee held a hearing Tuesday morning on the use of military equipment by police departments, and the federal programs that make it possible.

From any ideological angle, the trend — led by the now-infamous Department of Defense 1033 Program — has become problematic. To Tom Coburn (R.-Okla.), police militarization is a grave matter of government overreach. To Claire McCaskill (D.-Mo.), it's a worrisome sign that peaceful protesters can now quickly become "enemy combatants."

"Like many of you, I saw armored vehicles with a sniper pointing a rifle at an unarmed protester on a warm summer afternoon," McCaskill said. "I think most Americans were uncomfortable watching a suburban street in St. Louis being transformed with vivid images — powerful images across this country — into a war zone, complete with camouflage, tear gas, rubber bullets, armored vehicles and laser sights on assault weapons."

Amid all the bipartisan questions over whether local police really need such equipment to serve and protect the public, it's striking how far this conversation has come from one of the most popular law-and-order refrains in politics over the last 40 years: that we must, in all ways, be "tough on crime."

For decades, that idea has dominated sentencing policy, political ads, local police tactics and federal law-enforcement support. "Tough on crime" became intertwined with the "war on drugs." It yielded "three strikes" laws and mandatory minimum sentencing. It drove the unmatched rise of American incarceration. It justified the deployment of harsh police tactics and the need for meaner equipment, both of which have been used beyond drug crime. It became a potent political label, the only acceptable adjective: If you're not tough on crime, then you don't have anything worth saying about crime at all.

The sentiment was fanned in the 1960s by Richard Nixon, who believed that the "solution to the crime problem is not the quadrupling of funds for any governmental war on poverty but more convictions.” It was echoed by Ronald Reagan, who ran for president on the promise to "get tough" on street crime.

Today, "tough on crime" appears to be decidedly in retreat, as conservatives have begun to balk at the financial costs of incarceration, and as liberals have objected to the costs in civil liberties — and the disproportionate racial impacts — of aggressive policing. The rhetoric of "tough on crime" is fading. Here is the telling trajectory of the phrase in the archives of the New York Times:

Where the phrase has been infrequently deployed in Congress of late, it's often been in critique. Where it appears in Google today, it's "going out of style," it's "softening," it's "under revision" and dissection in the final "rise and fall."

In Tuesday's hearing, the sentiment never came up. And now that the country has winced at the sight of toughness taken to an extreme in Ferguson, the idea sounds crudely one-note, if not tone-deaf. Suddenly it appears quite possible to be too tough.