Historically, Republicans have had mixed success with this strategy. Jewish support for Democratic presidential candidates peaked during World War II; 90 percent of Jews voted for Franklin Roosevelt in 1940 and 1944, who won 55 and 53 percent of the overall popular vote in each of those years, respectively. Barry Goldwater, by contrast, was wildly unpopular among the Chosen People, winning only 10 percent of the Jewish vote in the 1964 presidential election. Almost three decades later, George H.W. Bush won only 11 percent of the Jewish vote in the 1992 presidential race. At times, Republicans have also had a bad habit of saying and doing things that seem anti-Semitic—like Bush Senior's secretary of state, James Baker, who infamously said "fuck the Jews" in a private conversation about Israel with a co-worker, or Richard Nixon, who had one of his staff members count the number of Jews who worked at the Bureau of Labor Statistics.
On the other hand, Jimmy Carter only won 45 percent of Jews' votes in his doomed run against Ronald Reagan in 1980; Walter Mondale won 67 percent of the Jewish vote in 1984. The point is that "the Jewish vote has ebbed and flowed over the years," said Herbert Weisberg, a professor emeritus at Ohio State and the author of a forthcoming book on historical Jewish voting patterns.
"Particularly during the Clinton years, [support for Democrats] really increased, reaching nearly 80 percent," he said. "But when you look back at the '70s and '80s, Republicans were getting about 30 percent of the Jewish vote. It looks like it’s going back to where it was [then]."
Midterm elections are also distinct from presidential races, particularly in terms of the issues people care about.** When the president is unpopular, it seems to work in the favor of the opposing party. This happened in both 2006 and 2014: At a time when George W. Bush was very unpopular, Democrats did well among Jews and American voters in general; and last week, Obama's unpopularity had the same salubrious effect on Republicans. It's also worth noting that overall voter turnout plummets during midterm elections, and in general, midterm voters tend to be older and more male, and this may have affected the poll results among Jews. (The 2010 data collected from exit polls about how people voted didn't have a big enough sample size of Jews to make meaningful comparisons with how they voted that year.)
For Jews in particular, it's usually assumed that Israel is a decisive factor in influencing voters' decisions. But Weisberg said that's unlikely in midterm elections; if anything, Israel would be more influential in presidential elections.
Even then, said Ester Fuchs, a professor of political science at Columbia University, most Jews probably don't vote based on what's going on with the relationship between Israel and the U.S. Despite vast support for the Jewish state among Republicans, GOP politicians still haven't won over even close to a majority of Jewish voters. "Efforts to shift the Jewish vote over to Israel haven’t really worked," she said. "The more assimilated Jews are, the less important Israel is to them."