The IRP is one of just eight registered parties, and it is the leading opposition party in Tajikistan. Its decision is likely to raise doubts about whether the upcoming poll is truly an alternative election, despite early announcements from five competitors to incumbent Imomali Rakhmonov.
The IRP and its approximately 23,000 members lost their leader in August when Said Abdullo Nuri died after a long battle with cancer.
When Nuri's deputy, Muhiddin Kabiri, officially took the reins in September, the IRP was engaged in a bitter internal debate over possible candidates. Some reports suggested the party was close to a split.
The IRP is still together. But on September 25, Kabiri announced the IRP would not field a presidential candidate. In an interview with RFE/RL's Tajik Service, he portrayed the move as one taken in the national interest.
"There is not just one reason. There are several elements, one being the unsuitability of the international situation and the reservations about Islamic political forces," Kabiri said. "There is also a lack of mutual trust between the international community and us. This was an important element in our decision; we didn't want to put Tajikistan in an awkward position. In other words, we didn't want to place our country and our party at the front line of criticism that Islamic movements are very active here. We have once again sacrificed our rights so as not to block possible aid to Tajikistan."
The IRP is the only officially registered Islamic party in any of Central Asia's five post-Soviet states. In the 1999 presidential election, an IRP candidate, Davlat Usmon, was voters' only alternative to Rakhmonov.
Lonely At The Top
The last presidential election in Tajikistan was held barely two years after a peace deal was signed, ending a five-year civil war (1992-97). There were major problems at the time in registering candidates. Countries and organizations that signed on as guarantors of the peace, particularly the OSCE, worked feverishly to try to make the election free, fair, and competitive.
Three people initially hoped to challenge Rakhmonov, but the other two failed to meet registration requirements. And IRP candidate Usmon's bid can hardly be called a "challenge."
Usmon was insisting up to election day that he was not a candidate. The election was something of an embarrassment for nearly all involved, as Rakhmonov garnered 96 percent of the vote.
Two other parties have already said they will not put forward candidates.
The Democratic Party of Tajikistan announced on September 24 that it will boycott the balloting. The Democrats' acting leader, Juma'boy Niyazov, told RFE/RL's Tajik Service why: "There is huge interference in the election by the authorities, especially in the regions. That is why there is little opportunity to have free and transparent elections. And that is why [our party] convention came to the conclusion to boycott the elections."
The Democrats have already suffered a major setback. Party leader Mahmadruzi Iskandarov was convicted of terrorism, banditry, and theft of state property in October 2005 and sentenced to 23 years in jail. His party continues to maintain that the charges were politically motivated.
Another group, the opposition Social Democrats Party, has condemned the upcoming vote as unfair. Party Chairman Rahmatullo Zoirov has rejected the validity of a 2003 referendum allowing incumbent Rakhmonov to seek reelection despite a constitutional limit of two terms.
"Since the entire process is not based on the constitution and the law, we consider the results of the [upcoming] election illegal and illegitimate," Zoirov told RFE/RL. "We demand that the election be restarted in the future."
President Rakhmonov's People's Democratic Party unanimously selected him to be the party candidate in a vote on September 23. The names have already emerged of five men who hope to challenge him.
The Communist Party, which backed Rakhmonov in the 1999 presidential vote, will field a candidate (Ismoil Talbakov), as will each of the Socialists' two factions (Abduhalim Gafforov and Mirhuseyn Narziev), and two newcomer parties -- the Party of Economic Reforms (Olim Boboev) and the Agrarian Party (Amirkul Karakulov).
Three of those men are relative unknowns who could face an obstacle gathering the 160,000 signatures for registration.
Any challenger will have his hands full in challenging the well-entrenched Rakhmonov, who has led the country since 1992. Some have even speculated that several of the candidates have entered their names simply to help give the appearance of a truly alternative poll.
Analysts have suggested that Rakhmonov could win this election easily. But the international community might judge this election to be even more predictable than the 1999 presidential vote.
(RFE/RL's Tajik Service contributed to this report.)