JEFFERSON CITY, Mo. — Nearly four years after he resigned from office and retreated from the capital city, former Gov. Eric Greitens returned Tuesday to officially launch his bid for U.S. Senate. “No matter what the mainstream media does, no matter what the Republican establishment does, no matter what the Left does, we’re going to win this race,” Greitens told a group of reporters after he submitted paperwork to run in the Aug. 2 Republican primary. Tuesday marked the first day of candidate filing for the primary. Greitens joined more than a dozen other Republicans in filing paperwork to run …