By Josephine Walker WASHINGTON (Reuters) - Republican U.S. Army combat veteran Sam Brown on Monday launched a run for his party's nomination to challenge Nevada Democratic U.S. Senator Jacky Rosen in 2024. Rosen's is one of about eight competitive Senate seats that Democrats will need to defend next year if they are to hold their narrow 51-49 majority in the chamber. Brown placed second in Nevada's Republican Senate primary last year with 34% of the vote, losing to former state Attorney General Adam Laxalt. Laxalt, a proponent of former President Donald Trump's false claims of election fraud, ...

