What this means is that Reid thinks regular Americans won't vote for him:

Reid's immigration push vital to his reelection hopes By: Susan Ferrechio

Washington Examiner

Chief Congressional Correspondent April 22, 2010

Immigration reform, once considered dead for the year, has been thrown a lifeline by Senate Majority Leader Harry Reid, D-Nev., whose revival of the legislation could energize his state's Hispanic voters and help save himself from defeat in November.

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However, as Steve Sailer points out, Hispanic immigrants frequently don't bother to vote.