Obama and Hillary were looking for non-specific dirt on Trump; Trump was requesting help with a specific ongoing criminal investigation into the origins of the Mueller probe, some of which were in the Ukraine and with an investigation into specific criminal acts by Joe Biden. The results of these investigations are of significant importance to the interests of the United States and it citizens, not merely to the Trump campaign, and so fall well within the responsibility of the President of the US and his attorney general to ferret out. By the way, the aid Trump withheld was supposed to be sent in February, five months prior to the phone call. If Trump was using this aid to coerce the Ukrainian President, why would he wait 5 months to call? In another btw, in the official transcript of the call, Trump never mentioned this aid in any way during the phone call and promised nothing in return for investigating Biden.

Knowing how to avoid breaking the letter of the law, (and since the investigation was shelved, no one really knows if there was criminal activity,) doesn't change the fact that this was corrupt and sleazy. And this is a long time pattern for Biden and his family, and Pelosi, and other Democrat/socialists, who have questionable dealings in the Ukraine that they don't want exposed. Of course since they're Democrat/socialists they can depend on the propaganda press to cover for them and refuse to report their corruption, and should their actions be exposed the propaganda press will excuse and defend them.