Probably Trump. The Trump strength with unions and Polish voters needs not to be understated. Whitmer and Stabenow won it narrowly, but they were very different races and without Trump being a factor, the county would not have been close in either race.
Though, I do expect Trump to maybe regress a bit, particularly in the southern part of the county, but he may improve in the northern, more exurban part of the county. 54-42 was the 2016 margin, I expect it to be 53-44 or so. Baris has Trump improving there though, who nailed Michigan 2016 (though he has Trump down in the state currently), but I remain skeptical.
Excuse me Mr REP, I have some questions for you.
1: Which polls are fake and which are real?
2: Who is the Election Mafia?
3: Do you think that Trump will be reelected?
4: Do you think that women are inherently inferior to men? (according to screenshots many on Atlas have seen)
5: Who hurt you?