Schumer came with Democratic Sens. Robert Menendez of New Jersey and Richard J. Durbin of Illinois. Graham and McCain brought fellow Republican Sen. Mike Lee of Utah. It was clear to the senators that one voice could prove crucial to their hope to sell a plan to conservatives: Sen. Marco Rubio, a Florida Republican and Cuban American with conservative credentials, who could become a champion untainted by past scars over immigration. Soon after that meeting, Durbin was in the Senate gym and spotted Rubio pedaling a stationary bike. "Marco, you got to be there," Durbin said. "I want you there...