Twice now this year, Rand Paul has flanked the Obama Administration from the left. The first time, when Paul staged a dramatic thirteen-hour talking filibuster to protest the government’s secretive drone-assassination program, the episode could have been written off as an opportunistic stunt. But with his latest move as the tacit leader of the disorganized libertarian-populist movement, Paul staked out less impeachable ground: America’s cruel, racially biased, and generally nonsensical drug-sentencing laws.

Attorney General Eric Holder announced last week that the Justice Department will ease enforcement of mandatory minimums, the federal prison sentences that compel judges to lock up even nonviolent and first-time offenders of some drug laws regardless of the details of the case. Five, fifteen, and in some cases life sentences were first made mandatory for drug crimes with the Anti-Drug Abuse Act of 1986, legislation passed amid the hysteria of an urban crack epidemic and Ronald Reagan’s war on drugs. Aided by such laws, the federal prison population has grown roughly 800 percent since 1980, with nearly half of all inmates held on drug charges. The status quo is untenable for reasons fiscal and philosophical, and Holder’s decision was widely heralded as a welcome policy shift. Not everyone was convinced, though. For reformers who once hoped that Barack Obama would make a sincere attempt to address the outrages and immoralities of the war on drugs, Holder’s speech smacked of politicking — a double hedge against the right’s libertarian awakening and the left’s charges that the administration has done nothing on the issue.

I discussed Holder’s move with Neill Franklin, a thirty-four-year veteran of the Maryland State Police and the Baltimore Police Department who serves as the executive director of Law Enforcement Against Prohibition (LEAP), an organization of current and former officers and officials working to end the war on drugs. “Too little, too late,” he told me. Franklin appreciates that the government’s highest-ranking criminal-justice official admitted to a failure of the system, but he is wary of being fooled twice. In October 2009, Holder’s Ogden Memo vowed to respect states’ rights where medical-marijuana laws were concerned. But by the end of Obama’s first term, the Drug Enforcement Agency had raided and closed more than four times as many state-approved marijuana shops than were shut down during George W. Bush’s eight years in office. From Montana to California, the DOJ, DEA, and IRS worked in concert to do precisely what the administration had vowed not to do.

“I’m from a place where if you recognize a problem, you do your best to tackle and fix the problem,” says Franklin. “The political world is different.” Franklin’s LEAP does not have the political leverage (read: money) of other special interests tied to the prison and law-enforcement industries, but its members are drug-war veterans who came to see the system as a fundamental offense against society.

For those unfamiliar with the moral crisis of the American penal system, let’s review the current state of affairs. The United States incarcerates a higher percentage of its people than any country in the world, far exceeding rates in China, Iran, and Russia. Americans make up just five percent of the world population, but with 2.24 million people behind bars, boasts 25 percent of the global prison population. These numbers are compounded by the justice system’s systematic racial bias. White and black men use marijuana at roughly equal rates, but according to a recent report by the American Civil Liberties Union, black men are nearly four times as likely to be arrested for possession. In her book The New Jim Crow, Ohio State University law professor Michelle Alexander writes that in some cities, African-American men are imprisoned on drug charges twenty to fifty times more often than white men. And The Economist reports that today in America, a black man is 3.6 times more likely to be jailed than a black man was in Apartheid South Africa in 1993.

It’s hard to disagree with critics like Franklin who say that the system is broken. But from another perspective, the system is working exactly as designed. It’s working so well, in fact, and for so many politically connected interests (private prison corporations and law-enforcement unions among them), that the two most powerful officials in the country, two men who are ostensibly sympathetic to the problem and who are black themselves, do not have the political leverage to address the underlying issues.

Before Holder’s speech at the American Bar Association last week, the Obama Administration and the Democratic Party were in danger of ceding leadership on the prison crisis to the junior senator from Kentucky. In March, Rand Paul joined with Senate Judiciary Committee chairman Patrick Leahy (D., Vt.) to co-sponsor the Justice Safety Valve Act, which would grant judges the latitude to apply shorter sentences for some drug crimes. In an April op-ed, Paul defended the bill on financial, moral, and political grounds. He noted that the federal prison budget has doubled in ten years to more than $6 billion, with nearly half of that money spent on nonviolent drug offenders. “Some are simply drug addicts,” Paul wrote, “who would be better served in a treatment facility.” In July, Utah Republican Mike Lee and Illinois Democrat Dick Durbin followed Paul and Leahy’s initiative with their Smarter Sentencing Act, which would also give judges more discretion over sentencing, and would retroactively reduce jail time for some inmates currently serving mandatory minimums.

Franklin says he doesn’t do politics, but he knows how the game is played. As he sees it, Holder had two motivations. First was this weekend’s fiftieth anniversary commemoration of the March on Washington. “You’re going to see thousands and thousands of black people marching on Capitol Hill with signs about our broken criminal-justice system and racial profiling and signs that reform is needed,” says Franklin, who also plans to march. Holder’s move, he says, “takes a little wind out of the sails of Saturday’s protests. The administration can say, ‘We recognize the problem and are moving towards reform.’ ”

Second, Franklin says, the Obama Administration “doesn’t want the G.O.P. to get out ahead of them on this.” The Republican Party has spent decades fortifying its tough-on-drug-crime reputation, and while Paul won’t change perceptions of his party with one bill, he might get there eventually. “It makes sense for the Republican Party to support this type of reform,” says Franklin. “It’s about smaller, less intrusive, and less expensive government.”

As the policies of libertarian populism come into focus, Rand Paul’s threat to the establishments of both parties will likely increase. He doesn’t have to adopt his father’s strident purism — Ron Paul wrote that drug prohibition of any kind is “incompatible with a free society” — to push an agenda of sensible reform. The Democratic Party won’t credit him with leading on an issue that should be theirs, and the G.O.P. establishment still can’t decide whether libertarians pose a path to victory or an existential threat. But Paul is nimbly pushing his own agenda to the fore. And with popular opinion about America’s drug laws squarely on his side, the rest of Washington will have little choice but to keep up.