Trump's ex-campaign chairman Paul Manafort has pleaded guilty to two counts of conspiracy and will cooperate with Robert Muelle's investigation of Russian election meddling.

The debate over what does and what doesn't make a campaign finance violation is taking over American politics- And of course the debate over what should happen to the President if his actions do constitute a violation.

But the latest legal developments include a warning from Robert Mueller that his inquiry is ready to subpoena the president if he refuses to appear before investigators.

Special Counsel Robert Mueller is investigating suspected Russian meddling in the presidential election.

The Dutch son-in-law of one of Russia's richest men was sentenced on Tuesday to 30 days in prison and fined €16,000 for lying to Special Counsel Robert Mueller's investigators about contacts with an official in President Donald Trump's 2016 campaign.

US President Donald Trump takes aim at Robert Mueller and the Russia investigation on Twitter.

As Trump continues his Twitter campaign against Robert Mueller's Russia probe, top Republicans take to the airwaves to warn Trump: Let the Special Counsel do his job.