WASHINGTON (Reuters) - President Donald Trump again attacked Special Counsel Robert Mueller’s probe into Russia and the 2016 U.S. election on Tuesday, reiterating that his campaign did not collude with Moscow and saying collusion is not a crime anyway.

FILE PHOTO: U.S. President Donald Trump walks behind his desk in the Oval Office during a swearing in ceremony for new U.S. Veterans Affairs Secretary Robert Wilkie at the White House in Washington, U.S. July 30, 2018. REUTERS/Brian Snyder

Trump commented hours before his former campaign chairman, Paul Manafort, was due to go on trial on tax and bank fraud charges in Virginia. As the first trial in the 14-month Russia probe, the case throws a fresh spotlight on a federal criminal investigation that has dogged Trump’s presidency.

Mueller is investigating whether Trump campaign officials worked with Moscow to try to sway the 2016 U.S. presidential election, something commonly referred to as collusion by the media and public officials.

“Collusion is not a crime, but that doesn’t matter because there was No Collusion (except by Crooked Hillary and the Democrats)!” Trump wrote on Twitter.

While collusion is not a technical legal charge, Mueller is probing any coordination between the Russian government and the Trump campaign, and could bring conspiracy charges if he finds that any campaign member worked with Russia to break U.S. law.

Legal experts said that working with a foreign national with the intent of influencing a U.S. election could violate multiple laws. “Collusion is basically a partnership in crime, which is conspiracy,” said Randall Eliason, a former federal prosecutor and a law professor at George Washington University.

Trump has for months denied that the campaign colluded with Russia to try to engineer his victory against Democratic candidate Hillary Clinton, and he bristles at the suggestion he might owe his White House victory to Moscow.

On Tuesday, he echoed his personal lawyer, Rudy Giuliani, who said in television interviews on Monday that collusion is not a crime. The strategy may be the latest in Trump’s efforts to strip legitimacy from the Mueller probe, which he has long denounced as a “witch hunt.”

Russia has denied the finding of U.S. intelligence agencies last year that it interfered to sway the election to Trump.

“The reason the Trump troops are pounding the ‘collusion is not a crime’ drum is because they colluded (better known as conspiracy, or aiding and abetting) and they want to get out in front of the story to control the narrative!” John Dean, President Richard Nixon’s legal counsel, wrote on Twitter.

Manafort, 69, faces 18 criminal counts, which center on allegations that he hid much of the $60 million he earned working for a pro-Russian politician in Ukraine in undisclosed overseas bank accounts and failed to pay taxes on it.