Recent polls suggest neither candidate has a lock on the issue. In a Washington Post-ABC News pollGallup/USA Today poll conducted in mid-May, Obama held a five-point edge over McCain as the candidate Americans trust more to handle immigration issues, but the Gallup/USA Today poll found the two about even, 36 percent said McCain would do a better job, 34 percent Obama.

The electorate is split deeply along partisan lines, with 68 percent of Democrats supporting Obama on the issue and 74 percent of Republicans favoring McCain in the Post-ABC News survey. Independents supported Obama by a margin of 12 points.

Personal economic situation plays a large role in determining whom Americans support on this issue. Those with household incomes of $50,000 or more per year supported McCain over Obama by an eight-point margin while those with less income favored Obama by 18 points. Moreover, Americans who reported having difficulty paying their bills supported Obama by 23 points and those worried about their standard of living supported the Illinois Democrat by 11 points.

One pitfall on this issue that could prove troublesome for both candidates, 19 percent in the Gallup survey, including a quarter of independents, said they trust neither candidate to handle immigration. One safe bet on this issue, both will be aiming to fill that void.