The Senate Intelligence Committee’s top Democrat warned the panel’s chairman over reports that the Republican worked with the White House to try to squash negative stories about Russian interference in last year’s U.S. elections, calling it a threat to the integrity of the top congressional probe into the issue. Senator Mark Warner, a Virginia Democrat, said expressed his concerns to Committee Chairman Richard Burr, a North Carolina Republican, and CIA Director Mike Pompeo, warning that he could pull the plug on what has been the one major congressional probe with bipartisan support.