President Obama hasn’t waded into the escalating debate over the rapid militarization of local police departments.

Politically, however, he can’t stay silent for long, as both his progressive base and civil libertarians are furious about what they see as the creation of virtual combat zones on U.S. soil.

The images of heavily armed officers in combat gear patrolling the streets in Ferguson, Mo., are inviting comparisons to Iraq, Afghanistan and other full-blown military conflicts.

It’s also putting the spotlight on a little-known program in which excess war gear is provided by the Pentagon to local police units free of charge. Through the Defense Department’s 1033 program, $4.3 billion of weapons, aircraft and tactical vehicles has been provided to local law enforcement agencies — including a half-billion dollars just last year.

That even includes items such as grenade launchers for local cops.

Attorney General Eric Holder said Thursday he was “deeply concerned” about the use of military equipment in Ferguson.

At the same time, however, the Pentagon defended the practice, showcasing the division within the administration surrounding the weapons transfers, which began in 1997.

"This is a useful program that allows for the reuse of military equipment that would otherwise be disposed of,” Pentagon press secretary Rear Adm. John Kirby said on Thursday.

Less clear is where Obama stands on the issue.

From a political perspective, the shooting of an unarmed Missouri teenager and subsequent standoff between police and protesters guaranteed that a relatively quiet dispute about the militarization of local police would command maximum attention from Democrats and Republicans alike.

“It was talked about among those who pay close attention, but nobody was listening,” Walter Olson, a senior fellow at the Cato Institute, said of the national conversation prior to the events in the St. Louis suburb.

That’s clearly changed in a post-Ferguson landscape.

“Everybody is angry. These are the types of images nobody can ignore,” a former Obama senior administration official told the Washington Examiner. “Obviously, the program predated the president, but he’s going to have to take a hard look at whether it makes any sense to turn police into combat forces.”

The White House did not return requests for comment Thursday on whether the president was exploring changes to the Pentagon program.

But lawmakers are already targeting the initiative.

“Our main streets should be a place for business, families, and relaxation, not tanks and M-16s,” Rep. Hank Johnson, D-Ga., said Thursday, adding that he planned to introduce a bill to prohibit the transfer of heavy military gear to local police.

Sen. Claire McCaskill, D-Mo., also expressed frustration with the weapons being used by police in her home state.

“We need to demilitarize this situation — this kind of response by the police has become the problem instead of the solution,” she said. “Today is going to be a new start, we can and need to do better.”

It wasn’t just Democrats putting pressure on the Obama administration to find different uses for the stockpile of military equipment.

“Washington has incentivized the militarization of local police precincts by using federal dollars to help municipal governments build what are essentially small armies — where police departments compete to acquire military gear that goes far beyond what most of Americans think of as law enforcement,” Sen. Rand Paul, R-Ky., said in an op-ed for Time magazine.

“When you couple this militarization of law enforcement with an erosion of civil liberties and due process that allows the police to become judge and jury —national security letters, no-knock searches, broad general warrants, pre-conviction forfeiture — we begin to have a very serious problem on our hands,” he added.

The 1033 program was established as part of the U.S. war on drugs, which also has come under increased scrutiny lately. The transfer of military-style weapons to law enforcement agencies was meant to help police combat drug cartels and other heavily armed criminal syndicates.

Although most U.S. police departments already had SWAT teams, the Pentagon program gave them an infusion of armored vehicles and other military-grade equipment. The thinking among most police departments, analysts said, was to claim the items just in case they could be used one day.

It remains to be seen whether the violence in Ferguson will lead to major changes or if such talk will fizzle out by the time lawmakers return from their summer recess in September.

Count Cato’s Olson among those skeptical of a major overhaul.

“My sense is that both parties’ fingerprints are on this stuff,” he said. “Both parties have been boasting about how much [military equipment] they’ve brought home.”

But Olson said lawmakers would have to answer a fundamental question central to the fate of the weapons initiative.

“Are we going to have a more violent relationship between citizens and police,” he wondered, “because we went so far in this direction?”