Iran's Rafsanjani: a cleric with a taste for secular power. Iran's recent reverses in the war against Iraq guaranteed a reshuffling of the military. But the appointment of House Speaker Rafsanjani as commander in chief was a surprising move - except to those familiar with his drive for power.

His appointment by Ayatollah Ruhollah Khomeini as commander in chief of all Iran's armed forces last week confirms his status as the Islamic Republic's second-most powerful man. And although he is very unlikely to follow Ayatollah Khomeini as Iran's official leader, Ali Akbar Hashemi Rafsanjani is poised to control actual power once the ayatollah departs from the scene.

Having the rank of hojatolislam - above a mullah, but below an ayatollah in the Shiite Islam hierarchy - Rafsanjani is viewed as having no chance at Iran's top post.

However, Khomeini's designated successor, Ayatollah Ali Montazeri, is a weak political figure and lacks Khomeini's charisma. Many Iranian and Western observers believe Rafsanjani hopes to manipulate Mr. Montazeri.

At the relatively young age of 56, Mr. Rafsanjani is already Speaker of Parliament. And the government takes no decision without the Speaker's approval. He is also provisional leader of Friday public prayers in Tehran, one of the most influential pulpits in the country. And, since February 1984, from the secret Khatam Oul Anbia headquarters in southern Iran, Rafsanjani has supervised military offensives against Iraq.

Rafsanjani's tightening grip on power in Tehran is all the more remarkable for having withstood a number of embarrassments.

It is widely believed in Iran - but has never been proved - that Rafsanjani was the key government figure involved with the United States in the Iran-contra scandal. Rafsanjani was also proved wrong when he insisted that the Soviet Union would not allow Iraq to fire Soviet-made missiles at Iranian cities. During April's ``war of the cities,'' Iraq rained more than 100 modified Scud-B missiles onto Tehran and other cities, claiming scores of lives.

Iranian journalists contacted in Tehran over the weekend say Rafsanjani's ambition as new commander in chief is to reduce the existing tensions between the Revolutionary Guards Corps and the regular Army. His final aim is to merge the two forces under a single leadership.

Rafsanjani will also try to convince the regular ground forces to play a more active role in the land war against Iraq, which has been carried out mainly by the Revolutionary Guards. On April 18, during a naval battle against US forces in the Gulf, Rafsanjani was reportedly struck by the lack of coordination between the Guards' naval units and the Iranian Navy. Both forces had their own chain of command, reporting to different officers.

Western diplomats in Tehran say if Rafsanjani succeeds in bringing the two forces into harmony he will have at his disposal a powerful lever to reinforce his own control over the country's political life.

Western observers as well as Iranian officials say that prior to the 1979 revolution, Rafsanjani was an obscure and rather low-ranking cleric who had graduated from the Qom theological seminary. Rafsanjani climbed up the ladder of Iran's Islamic establishment thanks to his political astuteness, these sources say.

``He loves the daily use of secular power and is very good at it,'' one official says. ``And moreover, he is a first-class orator and knows how to use the media.'' Rafsanjani's influence, coincidentally perhaps, reaches his country's media; his younger brother, Mohammad, is general manager of state-run radio and television.

A representative to the Iranian Parliament recently interviewed in Tehran said, ``From the early days of the revolution, Rafsanjani understood that our regime's weakness is factional fighting. He thus strove to get an image of mediator between the rival groups.''

This deputy also explains that by the end of 1979 Rafsanjani realized that the Islamic Constitution would confer tremendous powers to the legislative body and as a consequence to the one who would be capable of resolving the assembly's disputes. That apparently explains why he ran for and got the Speaker's job. Rafsanjani's foes are found among opponents to the Islamic regime as well as within the system itself. His detractors accuse him of being an unscrupulous opportunist driven by an inextinguishable thirst for power. ``He always flows with the tide,'' an Iranian journalist explains.

``Prior to the revolution he worked closely with moderates like Mehdi Bazargan. But when he felt Bazargan was persona non grata in the Islamic establishment, Rafsanjani didn't hesitate to insult him in public. Also, he had good relations with Tudeh [Iran's commnunist party] leadership. But when Tudeh members were arrested in 1983 he began attacking them with scathing words.''

Little is known about Rafsanjani's private life. Mrs. Rafsanjani has hardly been seen in public. A former Iranian minister's wife, once invited to the Rafsanjani home, says Mrs. Rafsanjani is a chador-clad woman who lives in her husband's shadow.

But like most traditional Iranian women, she is said to have enormous influence on him behind the scene. While he was jailed by the former government in the 1970s, his wife raised their three daughters and two sons. A few days after the 1979 revolution, Mrs. Rafsanjani used her body to shield her husband from an assassin's bullets. Both were wounded, Rafsanjani barely escaping death.

Claude van England, who visits Iran regularly, writes from Brussels.