Trump did cheat, in a way. Foreign actors clearly influenced those elections and Trump won with a minority in the popular vote. Democrats accepted that outcome and conceded the election. Many democrats gave Trump the benefit of the doubt. Barack invited him to the white house and allowed him to start the transition. All this even though many people already hated the idea of a Trump presidency.

I don't have to imagine the democrats did anything like the republicans are doing now, because it didn't happen.

Edit: here's a link to show you how small the margins were in swing states in 2016:

https://www.washingtonpost.com/graphics/politics/2016-electi...