I guess it's reasonable to argue over whether that's an offer of a bribe ("military aid and maybe a White House visit in return for investigating my political opponent") or an attempt at extortion a la the "encrypted your files and you have to send Bitcoin to me to get the key" cyber attack trend ("I've stolen your stuff, you only get it back if I get what I want").
But it's clearly one or the other, not to mention a separation of powers foul (Congress appropriated the aid -- the job of the executive, absent a successful veto, is to execute Congress's instructions, not to alter them for his own political benefit).
The evidence is airtight (including but not limited to a public confession from the president himself, corroborated by an official document he authorized the release of), so I'm puzzled to hear that House Democrats don't intend to include it in the articles of impeachment they'll be introducing later today.
From what I'm hearing, the articles will be two in number: "Abuse of power" and "obstruction of Congress." Which are fine, I guess, but they don't seem likely to be as compelling to voters as the personal corruption angle.
Do they think that not charging that part of the matter will reduce the heat on Joe Biden? If so, they've got another think coming. "But Democrats are corrupt tooooooooooooooo" is really the only card Senate Republicans have to play, and that's the card they'd play even if the charge was nuking Baton Rouge.