WHY IT MATTERS: Israel
As concern intensifies over Iran's nuclear program and the rise of Islamist governments in the Middle East, America's top ally in the region, Israel, has become increasingly wary. Israel's security has been a U.S. foreign policy priority of both Democratic and Republican administrations since the Jewish state was created in 1948. Although small in size and population, Israel has significant influence in Washington, and presidents of both parties have pledged their commitment to its defense. And it's always a potential flashpoint in a region that the U.S. depends on for oil.
Where they stand:
President Barack Obama has continued the U.S. tradition of strong support for Israel. Both American and Israeli officials say bilateral security cooperation is as strong as it has ever been. However, the Obama administration has become embroiled in several very public spats with the government of Israeli Prime Minister Benjamin Netanyahu, stirring criticism that Obama is not fully backing Israel.
Republican presidential rival Mitt Romney has been sharply critical of Obama's policy on Israel. Romney is friendly with Netanyahu, visited Israel in July and has vowed unreserved U.S. support for Israel.
Why it matters:
America has historically supported Israel as a bulwark of stability and democracy in the world's most volatile region and shares culture and values with the Jewish state. Israel has also been the United States' most consistent ally in the Middle East. Because many politically active American Jews and evangelicals rank Israel at or near the top of issues likely to influence their vote, Israel and its security are usually major election-year topics.
Israel sees a nuclear-armed Iran as a threat to its existence and the last three American presidents have stepped up pressure on Iran - which has threatened to wipe Israel off the map - to prove that its nuclear program is peaceful.
An Israeli attack on Iran, backed by the United States or not, could lead to retaliation from Iran and its proxies against Israel and perhaps Western interests. It could also set events in motion spiking oil prices. An Iranian attack on Israel would almost certainly draw the United States into a bloody regional conflict.
Presidents Bill Clinton, George W. Bush and Obama have all in turn tried to broker a two-state solution to resolve the Israeli-Palestinian conflict, which some believe would remove a main motivating factor for Islamist extremists who have targeted the U.S. and its interests abroad with terrorist attacks.
Romney, who has said he doesn't think Palestinians truly want peace, has taken issue with Obama's strategy in the peace process. He has criticized the administration for demanding that Israel freeze construction of Jewish housing on land that the Palestinians claim as part of their eventual state. After initially rejecting such a step, Netanyahu announced a temporary freeze intended to bring the Palestinians back to the table. But the talks quickly broke down amid complaints the Palestinians weren't serious about peace and Obama was putting too much pressure on Israel.