IMHO:  Political opposition research has been around for centuries but crosses the line when fabricated of lies or out-of-context information.  But especially if the information comes from ANY foreign government.

"The ethical dos and don'ts of opposition research" PBS NewsHour 7/13/2017

Excerpt

SUMMARY:  Donald Trump Jr. and his father, President Trump, have defended the decision to meet with a Russian government lawyer to potentially discuss information about Hillary Clinton as standard Opposition research.  Judy Woodruff speaks with Tim Miller a former Jeb Bush campaign official, and Christina Reynolds a former Hillary Clinton campaign official, discuss what goes into good opposition research.