Unless you live in Chicago, it’s a pretty good bet that you’ve never heard of Ed Burke. He’s an alderman on the city council, and on Thursday he was charged with attempted extortion. The Chicago Sun-Times reports:

“After serving on the City Council for nearly half a century, Burke faced a federal judge Thursday, accused of using his position as alderman to try to steer business toward his private firm.

“Burke, 75, now faces a maximum of 20 years in prison following an investigation that involved recorded calls on Burke’s cellphone and apparent federal surveillance of the alderman.”

And the fact that Burke is now in one hell of a legal predicament has Donald Trump very nervous, because Burke also happens to be a noted tax attorney who did work when the Chicago Trump Tower was being built. He managed to save the Trump Organization some $14 million in extra taxes, but many have wondered if he did so legally.

If indeed Burke wants to reduce the amount of legal exposure he’s facing, he has only once choice: Cooperate with prosecutors and agree to tell what he knows about anyone else he may have dirt on.

That’s where Trump comes into the picture. It’s long been suspected that the president cheats on his taxes, and there have been rumors for decades that he’s avoided paying city, state, and federal taxes on his earnings, not to mention possibly illegal write-offs that help him avoid tens of millions of dollars in taxation and penalties.

But the Burke indictment could also expose whether or not Trump has used laundered money to finance his building projects. If so, where did those funds originate? Russia? Saudi Arabia?

Ed Burke has every incentive to become the latest cooperating witness against Donald Trump, joining the likes of Michael Cohen and Rick Gates, both of whom can also provide information that will destroy Trump and his family.

The equation is simple: If Burke wants to avoid spending the next two decades of his life behind bars, he’ll agree to become Robert Mueller’s star witness.