TUCSON — They have rarely spoken in 17 months. Their relationship, as America now knows, turned testy before they parted ways. But as at many family reunions, the old feelings were set aside as Sarah Palin embraced Senator John McCain here on Friday and argued that he should not be unseated by a conservative challenger. “We need this new blood coming into the system and new party officials and folks who are willing to stand up and speak out for common-sense conservative solutions,” Ms. Palin said. “But we also need statesmen and heroes like John McCain to help us get...