Because Iran's current president, Hassan Rouhani, is too "moderate."

We're not sure who moved the rock, but Mahmoud Ahmadinejad has crawled out from under it and plans to run in his country's May presidential election. Fox News reports that the former Iranian president's decision "will upend an election many believed would be won by 'moderate' President Hassan Rouhani, who negotiated the nuclear deal with world powers."

"Though Rouhani has yet to formally register, many viewed him as a shoe-in following Supreme Leader Ayatollah Ali Khamenei's recommendation in September for Ahmadinejad to stand down," the report adds. Fox News adds: 

But many hard-liners in Iran seek a tough-talking candidate to rally around who can stand up to U.S. President Donald Trump. Ahmadinejad's candidacy also could expose the fissures inside Iranian politics that linger since his contested 2009 re-election, which brought massive unrest.

Associated Press journalists watched as stunned election officials processed Ahmadinejad's paperwork on Wednesday.

​Two of his former vice presidents have been jailed for corruption since he left office. Iran's economy suffered under heavy international sanctions during his administration because of Western suspicions that Tehran was secretly pursuing nuclear weapons. Iran insists its nuclear program is for peaceful purposes.

Ahmadinejad's disputed re-election in 2009 sparked massive protests and a sweeping crackdown in which thousands of people were detained and dozens were killed.

The memory of the 2009 unrest likely sparked Khamenei's comments in September. At that time, he recommended an unnamed candidate not seek office as it would bring about a "polarized situation" that would be "harmful for the county."

Ahmadinejad described comments by the Supreme Leader suggesting he not run as "just advice" in a news conference shortly after submitting his registration.

He said his decision to run was intended to help former Vice President Hamid Baghaei, a close confidant. Baghaei registered alongside Ahmadinejad on Wednesday.

Iran's May elections are viewed as a referendum on how the country will deal with the Trump administration moving forward.  

Ahmadinejad is of course best known for repeatedly denying the Holocaust, for publicly vowing to "wipe Israel off the ma,p" and for wowing American leftists with speeches delivered at Columbia University.