Couples line up at a mass wedding celebration sponsored by an Islamic charity run by the Muslim Brotherhood on July 6, 2012 in Amman, Jordan. (Karin Brulliard/The Washington Post)

Amid the rise of Islamist parties in Morocco, Egypt and Tunisia, the aftermath of the Arab Spring has often looked like an unstoppable victory march for the Muslim Brotherhood — “contagious successes,” in the words of a smiling Hamza Mansour, a top Brotherhood leader in this desert kingdom.

Yet even as the Jordan branch of the Brotherhood participates in a simmering protest movement that has shaken stability here, the group says it is pushing to ride the Islamist tide into electoral gains, not cause the collapse of a monarchy with which it has coexisted relatively peacefully since 1946.

“We are very realistic,’’ Mansour said. “The Muslim Brotherhood does not want to be solo.’’

That caution reflects the survivalist nature of an organization founded in 1928 as a Sunni revival movement in Egypt that has spawned affiliates across the Muslim world. While the region’s recent revolts have presented unparalleled opportunities for political payoff, experts say the Brotherhood has remained at heart a constellation of domestic chapters shaped by local regimes and dynamics, and groups like those in Jordan are wary of overreaching to grasp the revolutionary wave.

“The Brotherhood doesn’t do revolution,” Shadi Hamid, research director at the Brookings Doha Center, said of the Jordanian branch and its regional counterparts. “The Brotherhood wants to survive as a political force, so when change does happen, they’re going to be in a position to take advantage of it.”

Even then, the group’s ability to do so is not automatic. That was underscored on July 7 in Libya, where a liberal coalition bested the Brotherhood in national elections. The movement was long quashed in that country, as it was in Syria, where it has now resurrected to dominate a motley rebellion.

In other countries, the Brotherhood withstood suppression to cultivate popularity through mosques, charities and dogged organization. In Egypt and Tunisia, chapters were tolerated on the edges of political life, helping them emerge into nascent democracies with networks that delivered votes.

The Islamist rise is different in Arab monarchies such as Jordan, where rulers’ traditional legitimacy has served as a buffer against protests, which generally call for reforms, not the ouster of royals. Experts say the shifting winds have alarmed absolutist kingdoms such as Saudi Arabia, which once nurtured the Brotherhood but now views it as an ideological competitor, and the United Arab Emirates, where the Dubai police chief warned that the Brotherhood is “plotting to change the regimes in the gulf.”

Jordan, on the other hand, says it is following a path similar to Morocco, whose king responded to demands for change with more open elections that brought to power a government now led by Islamists, while reserving vast powers for the monarchy.

Jordan’s King Abdullah II responded to Arab Spring demonstrations with democratic reforms he says he long favored, including an end to restrictions on public gatherings, the establishment of an independent elections commission and a pledge to strengthen political parties for an eventual parliamentary government. He faces widening criticism that the moves are cosmetic, but the country’s divided opposition has not posed a serious threat.

‘A new era’

Against that backdrop, the Brotherhood has emerged as the potential spoiler in the king’s cornerstone reform effort: parliamentary elections to be held some time this year. That is because the Brotherhood runs the nation’s largest and only organized political party, making its participation key to the legitimacy of a vote.

Now the party, Islamic Action Front, is wielding that leverage to maximize its performance at the polls. Having sat out elections since a 2007 vote widely viewed as rigged, it is threatening to continue its boycott over a gerrymandered system that favors rural tribal candidates seen as loyal to the regime. A new draft elections law has allotted a greater share of parliamentary seats to parties, as the Brotherhood has demanded, but the group wants more. Many political analysts agree such an increase would be more democratic — and would boost the IAF’s power.

“We ask the regime to be on the side of the people,” said Mansour, the party’s secretary general.

Yet Jordan’s Brotherhood also claims to be daunted by the idea of assuming too much responsibility in a nation where the economy is foundering, the neighbors are strife-torn and the population is riven by ethnicity and class.

Jordanian royal court officials say Abdullah does not consider the Brotherhood a threat. But he has made clear attempts to appease it. He met with the group for the first time in nearly a decade early last year, as the Arab Spring began. Since then, he has publicly urged the IAF to participate in elections and ordered changes to the draft elections law as enticement.

And speculation swirled that Abdullah’s recent meeting in Amman with Khaled Meshaal, the leader of the militant Brotherhood offshoot that rules the Gaza Strip and was expelled from Jordan in 1999, was held to enlist him to the cause. Royal court officials said the encounter was only about the Palestinian peace process.

“We need to lay the foundations for a new era in Jordan’s political history,” Abdullah said on state television this month, adding: “Our doors and hearts are open to everyone, including the Muslim Brotherhood and their party.”

That tone is not entirely new. Jordan’s Brotherhood has operated openly since its foundation, when the monarchy viewed it as a useful partner against communists and leftists. The royal court says the relationship is a sign of Jordan’s commitment to political pluralism; many observers say it made the Brotherhood “loyal opposition.”

Relations degenerated as those threats faded and the Islamists grew stronger. Analysts say they worsened under Abdullah’s more detached reign and were complicated by Jordan’s support of U.S. anti-terrorism efforts and the war in Iraq. In recent years, Jordanian authorities have increased control over Brotherhood charities and mosques. The Brotherhood cut official ties with U.S. diplomats in 2003.

Filling a vacuum

Today, Brotherhood leaders’ rhetoric is light on religion. But they say regional currents are validating their perseverance and their belief in people power, clean government and defiance of the West. And Islamist views hold popular appeal among Jordanians, 72 percent of whom believe laws should strictly follow the Koran, according to a recent Pew Research Center poll.

“Islamic movements have always been the real opposition to these regimes,” said Jordanian Brotherhood leader Murad Adailah. As those regimes fall, he said, “it is the Islamist movement that will fill this vacuum.”

But the Brotherhood’s potential in Jordan is limited by a deep social divide between the rurally rooted “East Bank” Jordanians who dominate civil service and the more-urban Jordanians of Palestinian descent who reign in the private sector. Though it is not exclusively so, the Brotherhood is viewed as more Palestinian, and any overt political push could backfire, feeding existing fears that the group is trying to create a Palestinian state in Jordan.

“It is for the good of the Islamists to be a partner” in government, Adailah said. “Being alone would give us responsibilities beyond our capabilities.”

Still, the group faces suspicion.

“It is not true that what they are doing is defending the demands of the people,” said Labib Kamhawi, a political analyst and staunch critic of the monarchy. “They are using this slogan for their own political aims.”

That was not the view among celebrants at a Brotherhood-sponsored wedding celebration for 25 poor couples on a recent Friday in Amman, an example of the charity that has earned the group a following. Couples qualified by responding to a newspaper ad, and the Brotherhood paid for their dresses and suits, professional photographs and furniture for their first home. No religious or political credentials were required.

The men danced to Islamic music in a parking lot, the women in a tent. Political talk was oblique; one Brotherhood figure chided Jordanian leaders who flaunt wealth and urged grooms to become the opposite.

“I couldn’t have gotten married if not for the Muslim Brotherhood,” said Mamoun Dadas, 30. “If they boycott the election, I’ll boycott with them.”

But many in the crowd swore loyalty to Abdullah. “I’ve always voted for the Brotherhood,” said laborer Amad Moussa, 54, whose cousin was getting married. “But my priority is the king.”

Some strains within the Brotherhood favor a more aggressive approach. Jamal Abdulsalam Mansour, a leader of the student wing at Jordan University, said he firmly believes that Islam can right a wayward society and that the Brotherhood’s efforts to do that in Jordan were being weakened as leaders “turn a blind eye” to negative rumors about Islamists.

Mansour, 21, said he cried with joy when he learned that Brotherhood candidate Mohamed Morsi, a former political prisoner, had won the presidency in Egypt. But Jordan is not yet fertile ground for such rapid change, he said.

“The Jordanian people are not one. We cannot hold hands to push the regime,” he said.

“All I think about is working on the same method as Morsi,” Mansour said, referring to the Egyptian Brotherhood’s eight-decade wait for political power. “The rise of political Islam is inevitable.”