5 1/2 Reasons Why You Should Care About Iran Nuclear Talks
PHOTO: U.S. Secretary of State John Kerry speaks to the press upon his arrival in Geneva, Switzerland, Nov. 8, 2013.

The U.S. may be close to a deal with Iran.

In Geneva, Secretary of State John Kerry has met with his Iranian and European counterparts, seeking a temporary agreement for Iran to suspend nuclear enrichment and for the West to temporarily lift some economic sanctions. Talks ended Saturday without any agreement, and some of the momentum appeared to have slowed. The talks are set to resume Nov. 20.

Everything could still fall apart, but the U.S. and Iran are talking--it appears substantively--and that's something new.

ABC News: Inside Iran. Watch ABC's dispatches from Muhammad Lila, reporting from Iran.

So why should Americans care?

1. Iran is America's most powerful enemy state, and the U.S. can't do anything in the Middle East without thinking of Iran

The U.S. doesn't have many outright enemies that are countries. It's fighting a war against the stateless Taliban and waging a broader campaign against al Qaeda and its offshoots. Russia and China are competitors, rivals, and sometimes partners--not enemies. But relations with Iran have been openly hostile for decades, and any kind of agreement on this central issue--its advancement toward The Bomb--would be a major breakthrough.

Iran helped sow a rebellion against U.S. occupying forces in Iraq, and now it's lending assistance to Bashar al-Assad in Syria, the U.S. has acknowledged. Its allies in Hezbollah control Lebanon and in 2006 fought a war with Israel. Its elite military/intelligence force--the Quds Force--has been accused of bombings and attempted assassinations, and its agents tried to recruit a Mexican drug cartel to assassinate Saudi Arabia's ambassador to the U.S. at a restaurant in Washington, D.C., in 2011.

Inside Iran: Music Proliferates 'Underground'

North Korea is isolated, and while Venezuela and Cuba have held sway with other socialist governments in Latin America, Iran is a dominant player in its region. From Israeli security to Syria's civil war to America's relationship with Saudi Arabia, Iran looms as a consideration in almost every major issue in the Middle East.

2. A deal could avoid war--or cause it. If Iran gets closer, the U.S. or Israel may strike.

War remains on the table.

If Iran advances toward a nuclear bomb, Israel, the U.S., or both could attack, bombing nuclear facilities. In 2007, Israel struck a suspected Syrian nuclear facility; an Iranian nuclear facility was believed to have been infected with the Stuxnet virus in an international cyberattack.

The U.S. has said that, with Iran, it hasn't taken any options off the table.

"President Obama will not take any option off the table in this process, but we do seek to put to test the reality of the possibility of a diplomatic solution," Kerry said on Monday in Saudi Arabia, which has warned that Iran would use the bomb if it had one.

Inside Iran: ABC News Goes Inside 'Den of Spies'

A deal that halts Iran's nuclear program would lower the chances of military action. A deal that allows Iran to dupe the international community and keep enriching uranium while sanctions are lifted--as opponents in Israel and the U.S. Congress have warned--could nudge Iran closer to The Bomb and the U.S. and Israel closer to war.

3. Israel. America's most important Middle Eastern ally fears that Iran will get--and use--The Bomb

That's why Iran's steps toward the bomb are so troubling to the U.S. Iran doesn't think Israel should be a state; as recently as last week, Supreme Leader Ayatollah Khamenei--the most powerful man in Iran, who will control whether a nuclear deal is cut--called Israel an "illegitimate, bastard regime," the Jerusalem Post reported.

Israel has loudly protested the West's warming relations with Iran and has warned that Iran cannot, under any circumstances, obtain a nuclear weapon. The reason: Israel fears Iran would use it. The U.S. has maintained that any country bent on annihilating Israel shouldn't be given the weapon to do so.

"The deal that is being discussed in Geneva right now is a bad deal," Israeli Prime Minister Benjamin Netanyahu warned. "Iran gets everything that it wanted at this stage, and it pays nothing."

4. It's a test of Obama's foreign policy. A major agreement would instantly be his signature international achievement, behind winding down America's two wars

Remember when Barack Obama ran for president in 2008, and said he'd be open to talking to Iran without preconditions, and was criticized for it, and John McCain jokingly sang "Bomb, Bomb Iran" when asked about bombing Iran at a campaign stop, and then Obama won the White House campaigning against the perceived bellicosity of the George W. Bush administration, and then won the Nobel Peace Prize largely on his rejection war and promises of multilateral consent?

Inside Iran: Skateboard Diplomacy

He's still being criticized by Republicans for being too soft on Iran, after rallying international sanctions in 2010, as Congress pursued its own. The success or failure of these talks will reflect on Obama's approach.

The U.S. is hoping for a temporary deal--suspended Iranian enrichment, in exchange for lifting some of the sanctions--that would allow a major agreement to be reached in six months. If Obama and Secretary of State John Kerry can negotiate an end to Iranian's nuclear program, verified by inspectors, it would be a major victory for his presidency. If not, his critics will say, "I told you so."

5. Opening Iran: Is a closed nation ready for change?

As ABC's Muhammad Lila has reported extensively from inside Iran, Iranians appear ready for improved relations with the West--and for more access to the world in general.

Americans are advised not to go there. The State Department warns that "U.S. citizens may be subject to harassment or arrest while traveling or residing in Iran" and that Iran sometimes detains people and prevents them from leaving.

For the people of Iran, who are suffering economically under U.S.-led sanctions, a major agreement in six months would mean more economic opportunity. For Americans, it could mean better relations and an eventual opening of the country for trade and travel. That's the best case scenario. The U.S. helped overthrow Iran's democratically elected president, Mohammed Mossadeq, in 1953 and after the U.S.-backed Shah was overthrown in 1979 by the Islamic Revolution that rules the country today, relations have a long way to go toward pleasantness.

But even a shorter-term agreement would signify a political shift in Iran, after signs of openness to change in the last few years.

Hardline opponents of the U.S. burned flags in the streets this week to commemorate the anniversary of Iran's seizure of the U.S. embassy in Tehran in 1979, but progressives rose up to demonstrate in support of Mir-Hossein Moussavi after the election he lost to former president Mahmoud Ahmadinejad in 2009 and 2010. Those protesters didn't get Moussavi, but, three years later, Hassan Rouhani won the presidency and called it a victory for "moderation." More significant than his win, perhaps, was that Iran's religious leadership allowed him to win--seen by observers in the U.S. as a potential sign that Iran's clerical establishment was open to better relations with the West, too.

In a very noticeable way, President Rouhani has toned down the anti-Israel and anti-U.S. rhetoric employed by his predecessor, Ahmadinejad. Rouhani has been empowered to make a deal with the West over sanctions and nuclear enrichment, Suzanne Maloney of the Brookings Institution told ABC News when relations began to thaw this fall. If his push succeeds within Iran, there is some reason to hope for a more positive relationship between Iran, the U.S., and the rest of the world.

If not, the distrust will continue.

5 1/2. Syria. Iran stands between the U.S. and removing Assad from power

Iran is involved on the ground in Syria, the U.S. has acknowledged. The New Yorker reported last month that Iran's Quds Force is directing military operations for Bashar al-Assad and that its leader, Qasssem Suleimani, is one of the most powerful men in the Middle East. "Basically, Syria has become an Iranian protectorate," Netanyahu said last month.

The U.S. has pushed for a new round of talks on Syria, involving multiple countries, this month. Those plans fell apart, with the U.S. and Russia divided over whether Iran should play a role. The U.S. has insisted that, in order to take part in negotiations, nations must sign onto a preliminary agreement calling for a transitional government in Iran--likely meaning Assad's removal from power.

The current nuclear talks in Geneva ostensibly have nothing to do with Syria: according to the State Dept., Iran's nuclear program is the only topic, and no horse-trading will go on involving unrelated issues. So this is only half a reason, but improved relations with Iran, on any front, couldn't hurt the process of confronting Syria's tragic civil war.

More ABC News