This is not to say there aren’t crimes on the books that better match what Trump is alleged to have done. For instance, it is a campaign finance crime to knowingly and willfully solicit a campaign contribution from a foreign national. Given that Biden could be Trump’s next political opponent, an argument can be made that the Ukrainian investigation would be an in-kind contribution (a “thing of value,” as defined by the statute) to Trump’s campaign. The bribery of a foreign official like the Ukrainian president can also be a criminal violation of the Foreign Corrupt Practices Act.
But both of these statutes contain at least some of the problems presented by the bribery and extortion statutes. Courts won’t send presidents to prison for cajoling foreign governments to do things, even if that involves horse trading an official act by our government in exchange for an official act by someone else’s.
What Trump is alleged to have done is not a garden variety crime; it’s worse. It involved misusing $250 million in aid appropriated by Congress for his benefit—the kind of gross misconduct that easily clears the bar of high crimes and misdemeanors set by the Constitution when impeaching a president. Which means the best way to hold Trump accountable for that misconduct isn’t a criminal trial; it’s for Congress to impeach him.