Sen. Claire McCaskill called on Attorney General Jeff Sessions to resign for failing to disclose during his Senate confirmation hearing that as a senator he met twice with the Russian ambassador in 2016. U.S Attorney General Jeff Sessions arrives to attend a speech by President Donald Trump at a joint session of Congress in Washington , February 28. But his former campaign manager, Paul Manafort , has reportedly been investigated for contact with Russian Federation, along with other top Trump associates, and top Trump adviser Michael Flynn already had to resign his position as national security advisor for holding conversations with Kislyak between the election and inauguration.