(CNN) The biggest test of special counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election begins Tuesday with the trial of Donald Trump's former campaign chairman, Paul Manafort. The trial in federal court i n Alexandria, Virginia, is expected to last three weeks. The case against Manafort doesn't focus on his time as chairman of the Trump campaign in 2016. Manafort's tacticsHis lawyers have spent the months since Manafort's indictment attempting to pick away at the prosecutors' case with almost no success. Despite the suspected strength of prosecutors' case, Manafort expressed an air of calm confidence in private conversations before he went to jail in June.

Source: CNN July 31, 2018 10:09 UTC