LAS VEGAS – Sam Brown, the combat veteran who survived massive burn injuries in Afghanistan in 2008, called in some high-powered ground support for his quest to unseat first-term Democratic Sen. Jacky Rosen. Sen. John Kennedy (R-La.) joined Brown at a campaign office here Thursday to rally some three dozen volunteers in crucial get-out-the-vote efforts. In 2022, Democratic Nevada Sen. Catherine Cortez Masto beat former state Attorney General Adam Laxalt by just 8,000 votes, an average of four ballots per precinct. The Louisiana lawmaker lauded Brown as someone who’d fight for Silver State residents while pursuing fiscal responsibility. “Sam Brown is tougher than…