One quid pro quo between the Trump administration and Ukraine is well-established: Trump invited new Ukrainian President Volodymyr Zelensky to the White House in a May letter, and then his aides repeatedly dangled that meeting as a reward for Ukraine granting Trump his investigation announcements.
The other alleged quid pro quo, though — the one involving military aid — is more nebulous. It’s not clear exactly when Ukraine even became aware that the aid was being withheld, and it wasn’t as frequently tied to the investigations in talks with Ukrainians.