https://www.businessinsider.com/rudy-giuliani-trump-wont-answer-mueller-obstruction-of-justice-questions-2018-11"Trump's lawyer says Trump won't answer Mueller's obstruction-of-justice questions"
"President Donald Trump won't answer any questions from the special counsel Robert Mueller having to do with obstruction of justice, Trump's lawyer Rudy Giuliani
told the news website Axios in an article published Wednesday.
Trump submitted written answers for Mueller's Russia investigation on Tuesday but ruled out answering any future questions about his behavior as president, Axios reported.
The site said that Mueller did not ask specifically about obstruction of justice in this round of questioning but that Trump and his team had decided to stonewall further questions should they arrive.
While Mueller could subpoena Trump on his activities as president, Giuliani said Trump would refuse to cooperate.
"I don't think he has any way to compel testimony on obstruction because the argument of executive privilege would be very, very strong," Giuliani told Axios. "It all relates to a period of time after he was president."
ETA:
https://www.bbc.com/news/world-us-canada-46284895"The president's son, Donald Trump Jr, met a Russian lawyer during the campaign who was said to have "dirt" on Mrs Clinton, and former adviser George Papadopoulos has admitted lying to the FBI about meetings with alleged go-betweens for Russia.
Four people connected with Mr Trump's campaign and presidency - campaign chairman Paul Manafort, advisers Rick Gates and George Papadopoulos, as well as former national security adviser Michael Flynn - have been charged.
However, the US president denies any wrongdoing and no solid evidence has emerged to implicate him."