Even on the heels of November’s epic losses, the often-beleaguered Massachusetts GOP is heading into anticipated high-profile races with two power players — U.S. Sen. Scott Brown and former gubernatorial candidate Charlie Baker — setting up a potential GOP standoff over who will lead the embattled party in upcoming election showdowns. “I think that Republicans are depressed with the outcome of the last election, but the good news is we have really strong candidates,” said Richard Tisei, a Wakefield Republican who shared the ticket with Baker in the last gubernatorial election and narrowly lost against U.S. Rep. John Tierney this...