Washington - On a trip to Israel, Mitt Romney is trying to win over a tiny sliver of a small — but powerful — section of the American electorate. President Barack Obama is doing the same at home.

But while Romney's trip is unlikely to change the broader presidential campaign against Obama, he's hoping to close the gap among Jewish voters.

For all the wooing of American Jews in presidential campaigns, those who say Israel's fate drives their vote make up 6 percent of a reliably Democratic bloc. The tiny numbers are overlaid with an outsize influence. Campaign donations from Jews or Jewish and pro-Israel groups account for as much as 60 percent of Democratic money, and groups such as the American Israel Public Affairs Committee can bring strong pressure on candidates.

"This is going to be a close election. We are in a tight, tight race," said Democratic pollster Jim Gerstein. "But this race will not swing on the Jewish vote."