The argument would be that it was legitimate for Trump to investigate wrongdoing involving Hunter Biden.
There are numerous counterpoints to this (witnesses say the main thing Trump wanted was the announcement of an investigation, Trump doesn't seem to be calling for ethics investigations that aren't politically advantageous) but it would be a mistake for Democrats to pretend that everything to do with Hunter Biden was as perfect as Trump claims his phone call was.
What do you think Republicans will do in states with Democratic governors?
What will Democrats do to alienate minority voters?
The major change in the Democratic party has been the leftward movement of white people. Hispanics and African Americans are okay with centrists.
https://www.vox.com/2019/3/22/182598...ing-trump-2020
A Pew report does suggest that Democrats have moved a lot to the left, while Republicans have moved a bit to the right.
https://www.investors.com/politics/e...-extreme-left/
http://assets.pewresearch.org/wp-con...pe-release.pdf
This could be the way for a Trump to get reelected, so there are advantages to Democrats going with the types of candidates who won in swing congressional districts, as well as Governors races in Louisiana and Kentucky, rather than giving centrists reasons to worry.