Local lawmen don’t usually involve themselves in the affairs of state. It is their job to indict crooks and put them behind bars.

But when the affairs of state are corrupted by crooks, sometimes only a local prosecutor has the skills — and the sense of duty — that are required to address the crisis.

That explains why Wednesday’s criminal conspiracy indictment of House Majority Leader Tom DeLay, the Texas Republican who essentially runs the Congress, came not from Washington but from Austin.

The trail of sleaze left behind as DeLay has traversed the American political landscape over the past two decades grew so long and so foul that it begged questions about whether any legal action would be sufficient to clean up the mess made by the toxic Texan. Unfortunately, the Environmental Protection Agency has no program for cleaning up political Superfund sites like the one created by DeLay and his associates, so the nation’s only hope rested with a courageous Texas district attorney and a grand jury that had until this week to decide whether to indict the man who has done far more than George W. Bush or even Dick Cheney to turn Washington into a cesspool and the promise of American democracy into an ugly lie.

DeLay, who had a history of being disarmingly blunt about the pay-to-play commitments he expected from campaign contributors, and who secured the Congressional majorities needed to deliver for his corporate “partners” by warping the redistricting and electoral processes of his home state and others around the country, turned the Republican Party into what it is today: The most thoroughly corrupted political entity this side of the Standing Committee of the Chinese Communist Party’s Politburo. (So complete is DeLay’s control of the GOP that only a renegade Republican bsuch as Connecticut Representative Chris Shays was willing to admit the obvious: that the Texan’s ethical lapses have begun “hurting this Republican majority.”)

The Texas congressman, who after the indictment was forced to step down at least temporarily as Majority Leader, was so powerful that even Democrats in Washington treated him with kid gloves. Members of the opposition party might squawk when DeLay oversaw the redistricting of a half dozen Congressional colleagues out of their jobs, or when he warped the rules of the House to hold a trade vote open long enough to “break the arms” that were necessary to “win” it. They might even toss an ethics complaint his way. But, for the most part, top Democrats let the Republican representative known as “The Hammer” pound the political process into a shape that served his sordid ambitions. Though he was not actually the Speaker of the House, everyone knew that DeLay — who admitted he was “too nuclear” to hold the high-profile Speaker’s position when he gave it to his hapless sidekick, Denny Hastert, in 1998 — ran things.

So it fell to Travis County District Attorney Ronnie Earle to press the case that DeLay and two of his longtime associates — John Colyandro, the former executive director of a Texas political action committee formed by DeLay, and Jim Ellis, who heads DeLay’s national political action committee — had engaged in a criminal conspiracy to violate Texas campaign finance rules outlawing corporate contributions. Earle was the right man to make the case. With almost three decades of experience as the elected district attorney for a county that is the seat of state government in Texas, he has more experience prosecuting political corruption than just about any lawyer in the country.

Under Texas law, it is the Travis County District Attorney (who serves the capital city of Austin), not the state attorney general as in most other states, who is responsible for prosecuting criminal acts at the state level. Earle has taken that responsibility seriously, setting up a public-integrity unit that has a number of prominent politicians — 12 Democrats and 3 Republicans — with a record of success so impressive that the district attorney has been able to avert moves by angry legislators in both parties to cut the funding for the public-integrity unit or transfer its authority to the attorney general’s office.

Earle, a Democrat, has survived the assaults on his power to prosecute political wrongdoers because of his willingness to indict members of his own party and because of his own political purity — he once filed charges against himself for submitting a campaign finance report one day late.

Now that Earle has secured indictments of DeLay and his associates, however, he will be the target of one of the crudest smear campaigns in American political history — indeed, it has already begun. Republican operatives and their media allies claim the prosecutor is targeting DeLay for partisan reasons, while DeLay claims that “Ronnie Earle is trying to criminalize politics.”

Don’t believe it. Ronnie Earle is trying to get the criminals out of politics.