But the candidates still provide significant choices compared with elections in many other Middle Eastern countries.
The incumbent president, Hassan Rouhani, promotes economic and social freedoms. His main opponent, Ebrahim Raisi, the head of the country’s wealthiest religious foundation, opposes many such ideas and wants Iran to become more self-sufficient.
Televised debates this year have been held with new restrictions, in contrast to the live debates in 2009 that helped polarize the country. Campaigning is also controlled. Street rallies are not allowed. Instead, the candidates speak to their followers in stadiums and halls.
Ayatollah Khamenei used the speech on Wednesday to reinforce his determination that anyone “wanting to take any measure against the country’s security in the election will certainly receive a hard reaction and slap in the face.”
In accounts of the speech reported by the Tasnim News Agency and other Iranian news outlets, including Ayatollah Khamenei’s own website, he also accused George Soros, the multibillionaire Hungarian-American investor, of having tried to influence the elections of 2009.
That year, millions of Iranians took to the streets in protest, angered by what demonstrators said was fraud in the suspiciously lopsided re-election of the incumbent, Mahmoud Ahmadinejad.
After a crackdown, a series of mass trials and the house arrest of leaders of what was known as the Green Revolution, Iran’s establishment concluded that the entire episode had been plotted by foreigners.
“An evil American and rich Zionist said that he managed to turn everything upside down in Georgia with $10 million,” Ayatollah Khamenei said, referring to Mr. Soros and his alleged role in the 2003 Rose Revolution in Georgia.
“In 2009, he was foolish enough to try to affect the Islamic republic, but he slammed against a strong wall of national will and determination,” Ayatollah Khamenei said. “It is the same today.”
Mr. Soros’s representatives did not immediately respond to an emailed request for comment.
Ayatollah Khamenei is not the only leader who has accused Mr. Soros of interference. Right-wing groups in the United States have also spoken out against him. In April, Hungary’s government sought to close a university founded by Mr. Soros.