Obama and Fast & Furious - maybe? It depends if it was just bad policy or something more sinister and self-serving. If it was a larger conspiracy to violate federal law in an attempt to gain a case to impose gun control, then definitely. Trey Gowdy was unable to show that, however.
Bush and Iraq - probably not. I think virtually everybody would agree in hindsight that was bad policy. At the time, even Hillary and Kerry both voted in favor of the invasion. It turns out Saddam's deliberate misrepresentation of his WMDs was too effective. But, being that Congress passed the Iraq Resolution in 2002, I don't see it's impeachable. It was lawful bad foreign policy.
If a President is allowed to violate Congressional appropriation of funds, which is their sole Constitutional prerogative, for that Presidents personal political gain... then just imagine where that will go.
If the current Republican argument is taken to a further conclusion, then Rudy might as well start a firm on K Street in DC selling access to Trump and the alteration of other Foreign and Domestic Aid packages. Trump's attorneys, and the legislators that bought into it, have just said that would be acceptable and investigating it would be a violation of Executive Privilege. Maybe the next President will just give military aid in exchange for damaging information on a rival. What's the difference. Imagine where the next guy will take it from here.
Also, we're a Democratic Republic. Romney is not there to read the polls and chase the whims of the public. He's there to make decisions as he sees fit. The Senate gets the sole power to remove Presidents, not some convoluted electoral system where Senators are just required to vote to the popular vote of their respective states. It's the same reason that we didn't hear from John Bolton though over 75% of Americans wanted his testimony. We don't get the vote, the Senators do. If we don't like it we can vote them out when their term is over. (And no, a recall would not be acceptable under the US Constitution, regardless of what a State legislature says.)
My friend. I know you're too smart for the talking points.
None of this has anything to do with Trump vs Biden.
It has to do with massive amounts of money, $1.8 billion that was slid into Ukraine to prop up Privat Bank. Biden and Kerry did that. That $$$ is gone.
The owner of Privat Bank and Burisma, is the same Oligarch. Hunter Biden, was simply insurance to keep Joe Biden in line.
As for Obama, Bush.
You said "violate public trust". It violates the public trust to run guns into Mexico. Have those guns kill our border Patrol officers, then have Eric Holder protected under Executive Priveldge.
That was the standard you put forth, "public trust".
So by you're standard, all Trump had to do was declare "Executive Privledge"?
Get real.
Ukraine is a corrupt cesspool into which NGO, US State Department, and a pile of bad actors are dumping billions in taxpayer money into, enriching themselves.
There is a reason the same handful of names keep popping up in "Rusdian Collusion", "Ukraine", "Hunter Biden".
The reason is about $9billion from the US and IMF that got pumped into Ukraine since its "revolution" started and today.
FOLLOW THE MONEY.
Trump is just dumb enough to talk out loud. That's why he's a threat. Not some Patriotic BS, he simply talks to much.