President Trump's personal lawyer Michael Cohen leaves the U.S. Courthouse in New York on April 26. (Hector Retamal/AFP/Getty Images)

To understand the sorry state of federal public corruption law and its present inability to punish even the most egregious influence peddling, consider a hypothetical scenario involving President Trump’s personal attorney Michael Cohen.

Cohen was reportedly paid several million dollars over the past year by companies seeking an in with the Trump administration. For an administration that promised to “drain the swamp,” Cohen’s brazen behavior sounds decidedly swampy — Washington business as usual, only more so. But based on the publicly available evidence, Cohen’s behavior is slimy but likely not criminal.

In fact, it would take a great deal for Cohen’s activities to cross the line into criminal corruption. And that is the remarkable, and disturbing, aspect of the Cohen story: just how freely access to government power may be bought and sold these days without running afoul of criminal law.

Thus, a disturbing hypothetical: Even if Cohen explicitly sold access in the form of meetings with Trump administration officials — indeed, even if those officials themselves received a portion of Cohen’s fees in exchange for attending the meetings — it would be difficult, if not impossible, to mount a successful public-corruption prosecution.

For that, influence peddlers and politicians can thank former Virginia governor Robert F. McDonnell — or, more precisely, the Supreme Court justices who unanimously overturned McDonnell’s convictions.

McDonnell was found guilty of corruption after accepting more than $170,000 in secret gifts. But in June 2016, the court found that McDonnell’s favors for his benefactor — including sending emails, making phone calls and arranging introductions to other government officials — did not amount to “official acts” under federal corruption law. The court ruled that bribery requires a more substantial exercise of government power as part of a corrupt deal. Merely providing introductions or access to public officials is not enough.

The court in McDonnell v. United States endorsed an extremely cramped view of public corruption. A public official’s time and attention are finite resources, and access is valuable. For proof, we need look no further than the fact that major corporations were willing to shell out hundreds of thousands of dollars to Cohen, who offered little apparent relevant experience but was “promising access” to the new administration.

McDonnell allows such access to be sold to the highest bidder — not just by lobbyists but also by government officials themselves. After McDonnell, public officials are free to enrich themselves by offering access only to those willing to pay, because taking a meeting or a phone call is not an “official act.” And, of course, the everyday citizen or “little guy” who can’t pay gets left out in the cold.

White House budget director Mick Mulvaney displayed this mind-set recently when he said that while he was a congressman, “if you were a lobbyist who never gave us money, I didn’t talk to you. If you were a lobbyist who gave us money, I might talk to you.” Although Mulvaney’s comments provoked widespread outrage, McDonnell makes it clear that the practice he described is perfectly legal.

In Cohen’s case, a bribery prosecution would require proof that, in exchange for the payments, he secured agreements from Trump or other administration officials to perform specific official acts, such as lifting sanctions against Russia or pursuing a particular health-care or telecommunications policy. But proving such a clear quid pro quo is not easy. Personal connections may result in influence and tacit understandings that are simultaneously very real and nearly impossible to prove beyond a reasonable doubt. And that again explains why access itself can be such a valuable commodity.

Investigators for special counsel Robert S. Mueller III reportedly spoke months ago with companies that paid Cohen hundreds of thousands of dollars for “consulting services.” Prosecutors will no doubt follow the money in search of potential criminal violations. But those may be hard to find. In the current legal environment, politicians and those close to them are generally free to buy and sell access to government power with little fear of prosecution.

McDonnell was simply the latest in a series of Supreme Court decisions over the past two decades narrowing federal corruption laws. Cumulatively, those decisions have created multiple safe harbors for behavior that most would consider clearly corrupt. Congress could step in and reform those laws but has shown little interest in doing so.

Swamp, drain thyself? I don’t plan to hold my breath.