Evidence keeps piling up. Trump was directly involved, aid was formally withheld right after the call, AND they knew it was wrong so they kept it a secret. I've asked GAO to look into this. On top of abuse of power, I think it's a direct violation of the Impoundment Control Act. https://t.co/Of0VrosOwX— Senator Chris Van Hollen (@ChrisVanHollen) December 21, 2019