evidence: More than 200 Republicans who previously worked for either former President George W. Bush, the late Sen. John McCain, R-Ariz., or Sen. Mitt Romney, R-Utah, endorsed Vice President Kamala Harris for president in an open letter Monday obtained exclusively by USA TODAY. [...] If this sounds at all familiar, President Joe Biden’s 2020 campaign received similar backing from former Bush, McCain, and Romney staffers four years ago. The difference is, the number is even larger now. [...] These new endorsements, eagerly touted by the Democratic nominee’s campaign, came on the heels of Harris also picking up a variety of other Republican endorsements and Democrats including some GOP speakers at the party’s convention in Chicago.