More than 100 former staff members for Sen. John McCain are supporting Joe Biden, a show of support across the political divide that they hope amplifies the “Country First” credo of the former Arizona senator.

Some of McCain’s former aides who signed the letter include Mark Salter, the senator’s onetime chief of staff; Christian Ferry, who was deputy manager for McCain’s 2008 presidential campaign; Joe Donoghue, who was McCain’s legislative director; and Mike Murphy, a GOP political consultant who was a strategist on McCain’s 2000 presidential campaign.