1. There is no evidence at all that Joe or Hunter did anything corrupt. So no justification for the President of USA to pressure the President of Ukraine to investigated the Bidens.
2. Of all the supposed corruption going on in the Ukraine why is Burisma the only priority for Trump to pressure Ukraine on?
3. Why according to Sondland's testimony, was it only important that a public announcement be made regarding the investigation, rather than actually performing an investigation?
4. By law a certification was required before the aid could be released to Ukraine. That certification was issued by Undersecretary of Defense for Policy John Rood, who informed lawmakers that he "certified that the Government of Ukraine has taken substantial actions to make defense institutional reforms for the purposes of decreasing corruption [and] increasing accountability." - The appropriate due diligence had already been done by the appropriate people and had be passed.
Pentagon Letter Undercuts Trump Assertion On Delaying Aid To Ukraine Over Corruption