What's really behind the Christie-Rubio fight in the GOP presidential race
New Jersey Gov. Chris Christie on ABC's This Week (ABC/Screenshot)

WASHINGTON -- Two of the top contenders for the Republican presidential nomination used Tea Party support to defeat more mainstream candidates, voted against helping New Jersey after Hurricane Sandy, and opposed efforts to end the GOP-led 2013 federal government shutdown. But Gov. Chris Christie has to keep pace with only one of them to remain a…