Corruption doesn’t spring up from nowhere. Corruption is planted, fed and watered. Roots in the ground, out of sight, are what hold corruption in place.

Still, without a steady supply of nutrients — in the form of money, greed and opportunity — and without the right climate, corruption will not grow and produce more bad seeds.

Corruption needs help to survive. And the District of Columbia has a corruption climate to die for.

The city’s Office of Campaign Finance — the ostensible enforcer of rules governing political contributions and expenditures — is as ineffective as artificial sweeteners in curbing weeds. Limits on campaign contributions and disclosure rules are violated with impunity. The only thing the Office of Campaign Finance is good at is giving reporters a hard time.

Another weak link is the D.C. Office of the Inspector General. The OIG is scared stiff of elected officials and their well-connected friends. But when it comes to ferreting out waste, fraud and abuse by lower-level bureaucrats, the OIG can be a holy terror.

As if those two weren’t bad enough, the greatest corruption enablers of all can be found inside the John A. Wilson Building.

Yes, some members of the D.C. Council are the best friends the corrupt could ever hope for.

Ward 6 council member and mayoral candidate Tommy Wells (D) has distinguished himself from the pack. After former council member Michael Brown pleaded guilty this week on bribery charges, Wells said in a statement that the federal investigation into D.C. corruption revealed “pay-to-play laid bare.”

Calling the culture of corruption exposed by U.S. Attorney Ronald C. Machen “deep and pervasive,” Wells said it “has broken the public trust with our city’s elected leaders.” So true.

My only quibble with Wells’s statement is his reference to council members as “leaders.” Who would dare be led by that crowd? (Well, I might follow them — as part of a surveillance team.) To his credit, Wells also called for “tougher medicine for D.C. elected officials.”

But when the 13-member council had the opportunity to toughen campaign and ethics laws weeks ago, 12 wimped out. Wells’s legislation to curb the pay-to-play culture got only one vote: his own. The rest opted to protect business as usual.

“Nothing can stop our communities’ progress faster than a continued culture of corruption,” Wells declared in the statement.

At this stage, the only forces trying to prevent the District from becoming the District of Corruption are the U.S. attorney’s office, aggressive journalists and the newly formed D.C. ethics board, which is beginning to find its voice and muscle.

There have been some successes in the battle against government infestation.

Besides Brown’s guilty plea, former Ward 5 council member Harry Thomas Jr. is in prison; former council chairman Kwame Brown was forced out of office and pleaded guilty to a felony; and Jim Graham (D-Ward 1) has been reprimanded by the council and denounced by the Metro board for his actions on a land deal while serving as the council’s representative on the board.

None of that, however, appears to be ample deterrence.

Despite the prohibition on council members accepting gifts worth more than $20 from companies doing business with the District, Marion Barry accepted nearly $7,000 in gifts from two contractors working on D.C. government business.

Asked about the gifts this week, Barry dismissed the matter. “I don’t want to discuss it,” he said.

(Marion, how about when the city’s ethics office comes calling?)

Corruption is the D.C. government’s biggest enemy. The only way to get rid of it is with a full-scale assault. Anything short of that is useless. That means digging out the roots and their food sources: money, contractors on the hustle, politicians on the take.

Gardeners have a saying: “Pull when wet, hoe when dry.”

Thanks to Machen’s two-year investigation, the District is getting a soaking. Now is the time to dig down and pry up the tendrils of corruption: those straw donors who allowed their names to be attached to campaign contributions they didn’t make; contractors who disguise their political donations and evade contribution limits by using the names of different companies that they own; and elected officials who violate laws that they have sworn to uphold.

Corruption didn’t descend out of thin air. It is homegrown. And it must be killed.

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