The problem with using this Ukraine phone call as grounds for impeachment are this:
*The nature of the matter could easily implicate Biden, Obama, etc. just as much if not more than Trump.
*With all the questions surrounding Biden & his son in Ukraine, many people see no problem with Trump asking Ukraine to help look into it... Honestly, if roles were reversed, and it were Eric Trump being paid just short of $1,000,000 a year, Trump running for President, and President Biden called Ukraine to ask for help investigating candidate Trump... You think we'd be dealing with the amount of outrage that we're currently seeing?