Iran's former president, Ayatollah Ali Akbar Hashemi Rafsanjani, was buried Tuesday, and the large outpouring of grief at his funeral reflects the uncertainty facing Iranian moderates.

Rafsanjani may have risen along with the country's 1979 Islamic revolution that toppled the U.S.-backed shah, but in later years, his pragmatic streak and respected position made him a leading voice of moderation.

Rafsanjani was seen as one crucial pillar in the power base of President Hassan Rouhani, who won election in 2013 after the conservative Guardian Council rejected Rafsanjani's own candidacy. The other major source of Rouhani's support is another former president, Mohammad Khatami, who has effectively been under house arrest in recent years.

Rafsanjani's death, just months before Rouhani is expected to stand for re-election in May, leaves the moderate wing of Iran's political establishment without one of its most important voices.

"It really does create a political vacuum in some ways," says Ali Ansari, professor of Iranian history at the University of St. Andrews in Scotland. With Rafsanjani gone and Khatami under wraps, he says, this hole has opened up at a crucial time.

Ansari says the months ahead will be a real political test of whether Rouhani, who shepherded a controversial nuclear agreement with world powers past hardline opposition, has enough of a power base of his own to make up for the absence of Rafsanjani.

"You know, I have my doubts about it," he says. "I've never felt that Rouhani is as big a player as some of the previous generation."

At stake is Rouhani's — and Rafsanjani's — belief that Iran's best hope for the future lies in outreach to the world and better relations with other countries, not the inward-looking self-reliance often preached by Iran's hardliners, including Iran's supreme leader, Ali Khamenei.

Rafsanjani's legacy

In an appraisal in The New Yorker, Robin Wright wrote that Rafsanjani advocated better ties with the West, including America. Not long ago, he tweeted, "World of tomorrow is one of negotiations, not the world of missiles."

A different take on Rafsanjani's political legacy and the impact his absence will have on the political scene comes from Gary Sick, senior researcher at Columbia University's Middle East program.

"Contrary to some of my colleagues, my guess is that Rafsanjani's departure will have very little actual impact on the course of developments," he wrote in a .

"If I were in Rouhani's shoes, I would certainly be sorry to lose an ally with such sterling revolutionary credentials. After all, the centrists need all the friends they can get," he added. "However, the outcome of the next election will depend on Rouhani's ability to persuade Iranians that they are better off with the nuclear agreement and that he is capable of defending Iran's interests better than any alternative choice."

Last year's nuclear accord remains one of Rouhani's chief accomplishments, and it has brought an infusion of cash, as frozen overseas Iranian assets were released. There have also been major commercial aviation deals and a notable increase in Iranian oil exports since the deal. But economists say the benefits have yet to trickle down to the Iranian street, where they might do Rouhani some political good.

Presidential election in May

So far, Rouhani has not announced his intentions for the May elections, though supporters say he's likely to run again. Thus far, only a few other candidates have announced. Analysts say former Tehran mayor Mahmoud Ghalibaf may make another run.

Hardliners are eager to make Rouhani a one-term candidate. The man he succeeded, Mahmoud Ahmadinejad, has been mentioned as a possible contender, though a number of Iran analysts consider him unlikely to run.

With Rafsanjani's passing, the number of Iran's founding revolutionaries still in roles of influence is shrinking. Some analysts see an imminent "generational change" for the Islamic Republic. Ansari, for one, wonders if that change will mean more moderation — or less.

"I think the worry for some of us is that really, what you have with Khamenei and ... many of those in the Revolutionary Guard, but also the political elite following on, [is a group that's] much less interested in the West, and much more tied to a sort of Russian alliance," he says. "So it's not at all clear that the change in guard will lead to a more moderating influence."

Copyright 2021 NPR. To see more, visit https://www.npr.org.