The U.S. Navy aircraft carrier USS John C. Stennis is being rushed to the Persian Gulf as tensions between Israel and Iran edge closer to the boiling point.

The Nimitz class carrier, with an air wing of about 90 aircraft, sets sail Monday on an eight-month deployment to the region -- four months ahead of schedule.

In the gulf it will join the USS Enterprise Strike Group, giving the United States a powerful deterrent to any Iranian attack on commercial oil tankers in the Persian Gulf and Strait of Hormuz or a counterpunch to Iranian military action against U.S. military facilities in the region or those of its allies.

"It's tough," U.S. Defense Secretary Leon Panetta said to sailors recalled early from leave. "We're asking an awful lot of each of you. And frankly, you are the best I have -- and when the world calls, we have to respond."

Panetta said the Stennis Strike Group, which includes a guided missile cruiser and four guided missile destroyers, is necessary in the gulf to guard against threats to U.S. national security interests and "obviously, Iran is one of those threats," he said.

The word "crisis" has become nearly a synonym for the Middle East. U.S. and Israeli ally Hosni Mubarak, for decades the president of Egypt, has been ousted and replaced by a Muslim fundamentalist regime that has sent tanks to the Sinai border in violation of peace accords; and Syrian strongman Bashar Assad is battling a rebellion that has left thousands dead and threatens his demise.

Syria is known to have chemical weapons, which the West fears could fall into the hands of jihadist groups or be used in what is as close to a civil war as you can get in Syria.

But the United States is hindered in how much it can do to aid Syrian rebels - Assad is an ally of Iran, which funnels money and weaponry to Hezbollah in Lebanon, who in turn use the largesse in terror attacks on Israel.

Tehran has slammed Western powers and gulf allies for supporting the Syrian rebellion and warned of unspecified consequences.

Yet as serious as those issues are, none has topped the conundrum of Iran's nuclear ambitions, which Tel Aviv views as a direct threat to Israel's very existence, an existence that Tehran's leadership repeatedly vows to end.

"The very existence of the Zionist regime is an insult to humankind and an affront to all world nations," the official Islamic Republic News Agency reported Iranian President Mahmoud Ahmadinejad saying in a recent speech.

"Confronting Zionists will also pave the way for saving the whole humankind from exploitation, depravity and misery."

Annihilating Israel, he said, was the duty of humankind.

Iran's railing against the Jewish state is nothing new since the overthrow of Shah Reza Palavi in 1979 but Iran is now believed to have missiles capable of hitting Israel and is suspected of being intent on building a nuclear weapon.

Since Iranian dissidents first disclosed the existence of nuclear sites that Tehran had not reported to the International Atomic Energy Agency - a U.N. body - the Iranian government has played an unending game - agreeing to cooperate with international inspectors and then not doing so; agreeing to international negotiations over its suspected weapons programs and nuclear fuel enrichment, and then stonewalling on substantive discussions.

Iran is processing nuclear fuel at a 20 percent enrichment level, higher than that needed for civilian nuclear energy, which it claims are its true ambitions. Nuclear power facilities, it insists are a sovereign right.

IAEA reports show indications that Iran may indeed be moving toward acquiring a nuclear weapon.

Israel, meanwhile, has responded by warning it has a right to defend itself and a pre-emptive military strike against Iranian nuclear facilities is a distinct possibility, something which the West fears will draw them into a conflict that could spiral out of control.

Iran, for its part, has threatened to use force to close the Strait of Hormuz -- through which about 40 percent of the world's seaborne crude passes - strike back at Israel and also hit U.S. military installations in gulf countries.

International efforts to pressure Iran on its nuclear program and sidestep a military confrontation are hurting Iran but Tehran remains defiant. EU countries, which accounted for about 18 percent of Iranian petroleum exports, have stopped importation of oil from Iran and banned companies from insuring Iranian oil tankers or tankers carrying Iranian petroleum products.

U.S. sanctions, which bars financial dealings between U.S. banks and those abroad that facilitate payments for Iranian petroleum are also taking their toll on the Iranian economy, which depends on oil exports for about 80 percent of foreign exchange earnings. U.S. measures, however, allow for exemptions for countries that are heavily dependent on Iranian oil but are scaling back on their importation of it -- most notably, Japan, South Korea.

Others are believed to be engaged in sub-rosa deals with Tehran and Iranian front companies to obtain oil, but at lower prices that the Tehran regime would like.

Israel is doubtful of the efficacy of the sanctions regime and made it clear it will act with force to keep Iran from becoming a nuclear power. In recent weeks speculation has been rife of an imminent strike, possibly before the U.S. presidential election. Israel, however, is apparently divided on the issue.

Given the ratcheting up of tensions, two U.S. carrier strike groups in the Persian Gulf appears a sensible.