High hopes: Since Iranian President Mahmoud Ahmadinejad came to power in 2005, his country's economy has fallen into shambles and international ire against Iran has risen to the boiling point. Although the president has his supporters, many Iranians have become frustrated and hope for change, including the young woman above. She and other supporters of rival presidential candidate Mir Hossein Mousavi gather during a campaign rally at Haydarniya Stadium on June 9 in Tehran. Depending on the outcome of June 12's vote, Ahmadinejad's days as president could be numbered.

Fab four: More than 450 Iranians registered to run for president, but the 12-member Guardian Council only gave its seal of approval to four, pictured above. Clockwise from top left, they are: Mahmoud Ahmadinejad, the current president; Mir Hossein Mousavi, a reformist who was prime minister from 1981 to 1989; Mohsen Rezai, a conservative and former commander of the Revolutionary Guard; and Mehdi Karroubi, a moderate and former speaker of parliament. According to Iran's Constitution, candidates must be politicians or clerics, hold Iranian citizenship, and be Shiite Muslims who believe in the principles of the Islamic Republic. (Harvard University's Kayhan Barzegar has more on the policies and promises of all four candidates in this week's List.)

Winning hearts: Supporters of candidate Hossein Mousavi attend a campaign rally at Haydarniya Stadium in Tehran on June 9. The day before, thousands of Mousavi supporters -- mobilized in less than 24 hours through text messages and Facebook postings -- formed a stunning human chain along Tehran's Vali Asr, a 12-mile (19 km) arterial road that runs north to south through the capital. Decked out in shirts and head scarves that were grass green, the signature color of Mousavi's campaign, the supporters brought Tehran's traffic to a near standstill, with pedestrians winding their way home through stopped cars..

Making waves: Mousavi and his wife, Zahra Rahnavard, wave during a rally in Tehran on May 30. Many Iranians seem to favor Mousavi not because of who he is, but who he isn't -- Ahmadinejad. "Mousavi is so popular because many people dislike Ahmadinejad's policies," Iranian political analyst Majid Hoseini told the Washington Post. "He doesn't have any charisma. It's the worries in the society that will get him votes." One girl shouted from a car in Tehran on June 6, "I don't really know who he is. But he is the only one that can beat Ahmadinejad."

Going green: Mousavi supporters wear green and wave green, his trademark color, during a rally in Tehran on May 23. A reformist candidate, Mousavi draws much support from younger voters, who want to improve their country's international standing after the damage the firebrand Ahmadinejad wreaked. Critics say Mousavi was a hard-line revolutionary in the early years after the 1979 revolution and that he purged pro-Western academics from universities. Others say he is a changed man. "Mousavi evolved from a revolutionary to a pragmatic manager," Masoud Soltanifar, a former deputy governor of one of Iran's provinces, told the Washington Post.

Kissing up: President Mahmoud Ahmadinejad kisses a young girl as crowds greet him in the city of Semnan on May 20. He was elected in 2005, gaining support with his populist views. Today his base of support comes from working-class families and the Revolutionary Guard, which can mobilize millions of voters through its volunteer corps. The president has become more unpopular, however, due to Iran's economic problems and the international ire he has provoked by acts such as questioning the Holocaust and calling U.N. resolutions "worthless papers."

Wrapped in the flag: Despite his increasing unpopularity, however, Ahmadinejad can still generate a crowd. On June 8, an estimated 180,000 Ahmadinejad supporters -- many bused in by the Basij, Iran's volunteer paramilitary corps -- gathered at a central mosque in Tehran. The crowd was so thick that Ahmadinejad couldn't even make it to the podium to speak. Instead, he stood on top of his sport-utility vehicle for a brief time before leaving. Above, Ahmadinejad supporters wave Iran's flag -- the symbol of Ahmadinejad's campaign -- at an earlier rally on June 2.

Sticking around: Posters of moderate candidate Mehdi Karroubi gaze at women strolling in downtown Tehran on May 26. "Mahmoud Ahmadinejad" is sprayed in black Farsi letters across the posters. Karroubi could drain votes from Mousavi, the reformist, leading some to insist that he withdraw in order to consolidate the reformist vote with Mousavi. Karroubi has remained determined, however. "I will never withdraw. ... I believe the larger the number of candidates, the better," he told a news conference.

On the table: Supporters of candidate Mohsen Rezai, looking up from the poster, work at his campaign center in Tehran on May 28. "I propose to put together a package of eight or nine topics that the U.S. and Iran would work toward. What is important is to just start the talks," he told the Los Angeles Times. The former head of the Revolutionary Guard has a more belligerent tone when it comes to Israel, however. "My government ... knows exactly where Israel's sensitive spots are. It could stop them forever with one strike," he said last month.

Boy wonder: Among the Iranians who registered their candidacy but didn't gain approval is 12-year-old Kourosh Mozouni, above flashing the victory sign after registering in Tehran on May 8. He told reporters, "I will buy Hawaii, Obama's birthplace, from the United States and lease it to Israelis who will go live there -- so that they don't kill the children in Gaza." Other portions of his platform included a hardly youth-friendly ban on computer games and a prohibition on women working unless they've spent at least five years having babies.

Caught in the Web: With a Mousavi-green ribbon around his wrist, an Iranian youth surfs the Web at an Internet cafe in the western city of Hamadan on May 26. Authorities had just restored access to Facebook after blocking the social networking site on May 23. Mousavi has been using Facebook to mobilize voters, and reformists in general have turned to the Web to build support because they lack access to state TV.

War of words: Ahmadinejad, left, and Mousavi, right, prepare for their live debate on state TV in Tehran on June 3. Mousavi told the hard-line Ahmadinejad, "In your foreign policy, you have damaged the nation's dignity." After pointing out that previous U.S. administrations aimed to "topple" Iran, Ahmadinejad retorted, "Now the U.S. has officially announced that it doesn't seek to do so. ... Which foreign policy has reinforced the country's independence?" The debate was one of six held among the candidates. Additionally, this presidential campaign is the first in the Islamic Republic's history that has featured a series of live televised debates.

Last stand? Ahmadinejad arrives at a news conference in Tehran on May 25. "Ahmadi bye-bye" and "If they don't cheat, Mousavi will win" have become popular chants among Mousavi supporters. Ahmadinejad's and Mousavi's campaigns expect a close race. There are no credible polls, but one conducted for the government in early May found 58.6 percent for Ahmadinejad and 21.9 percent for Mousavi. A mid-May poll conducted by the state broadcaster put 47 percent of Tehran's vote for Mousavi and 43 percent for Ahmadinejad. At this point, anything could happen on June 12, including Ahmadi bye-bye.