MIAMI — The federal trial of a former Miami congressman accused of secretly lobbying for Venezuela’s government during the first Trump administration begins Monday with Secretary of State Marco Rubio set to testify over his interactions with his old friend. Prosecutors allege David Rivera was a hired gun for former President Nicolás Maduro, leveraging Republican connections from his time in Congress to push the White House to abandon its hard line on Venezuela’s socialist government. Rivera, who at one time had been Rubio’s roommate in Florida and co-owned a house with him, allegedly persuaded then Foreign Minister Delcy Rodríguez — now Venezuela’s acting president — to award him a $50 million lobbying contract to be paid by state oil company PDVSA. As part of the alleged foreign influence campaign, prosecutors say Rivera was aided by Texas Republican Rep. Pete Sessions and a convicted Cali cartel associate as he sought meetings with the White House and Exxon Mobil on Maduro’s behalf.…