But mistrust runs so deep on all sides that even the prelude to the negotiations has been a study in the kingdom's divisions and suspicions, and suggests a difficult route toward any possible accords.
The country's Sunni rulers—supported by the West and other Gulf allies—seek to bring the main Shiite factions back into the political fold in hopes of starting a gradual reconciliation on the strategic island, home to the U.S. Navy's 5th Fleet.
Envoys from the Shiite groups, however, remain wary of opening a process that they believe has no chance of reaching their goals: forcing the ruling monarchy to give up its monopoly on power and allow an elected government that would certainly include the majority Shiites.
Meanwhile, hard-line Shiite protesters demand nothing short of toppling the two-century-old dynasty. Such a showdown would likely prompt another round of military action from neighbors such Saudi Arabia, which sent in troops to aid Bahrain's Sunni leaders after the uprising began in February 2011.
There were no public statements as the various envoys entered a desert resort where the talks were held.
Security forces were deployed in mainly Shiites areas in anticipation of clashes.
Washington, which has supported the efforts for negotiations, has stood by Bahrain's monarchy because of its critical military ties and worries about fallout among other Gulf Arab states. However, U.S. officials have criticized harsh measures by Bahrain, including stripping 31 Shiite activists of citizenship, and faces mounting pressures to further trim military sales to Bahrain's government.
Bahrain's Shiites account for about 70 percent of the kingdom's more than 550,000 native-born citizens. While they are the majority, they claim they face systematic discrimination and are effectively shut out of top-level government and military roles. Shiites protests for a greater political voice have flared during the past decades, but the current unrest is the longest and most threatening to the ruling system.
More than 55 people have been killed in the clashes. Some Bahrain-based rights activists place the death toll far higher. Dozens of top Shiite political leaders remain in jail, including some sentenced to life terms.
Tensions also appear to be on the rise heading toward the second anniversary of the uprising on Thursday. Early Saturday, Shiite protesters set barricades of tires ablaze and government security forces lobbed tear gas canisters at the demonstrators.
Police have set up more checkpoints on main roads and security reinforcements have been deployed around the birthplace of the rebellion, Pearl Square in the capital, Manama. The square, ringed with razor wire and concrete barriers, is watched round-the-clock.
Bahraini authorities have offered a number of concessions to try to quell the violence, including granting more oversight powers to the elected parliament. The steps, however, fall short of Shiite demands to break the current system, which allows rulers to hand-pick Cabinet members and other key posts.
A statement from Al Wefaq, the biggest Shiite political group, said the talks must seek a "big political project that seriously represents the peoples' demands."
Bahraini officials have called the dialogue a chance for a "national consensus," but have been unclear on whether they would consider any reforms that would weaken their direct control over the country's affairs. A key challenge could be opposition calls to replace Prime Minister Khalifa bin Salman al-Khalifa, an uncle of the king who has been in office since Bahrain's independence in 1971.
The last round of talks in 2011 collapsed quickly. Al Wefaq delegates pulled out, saying the government was not willing to discuss political reform. Since then, accusations and recriminations from both sides have sharply intensified.
Bahrain's leaders and Gulf partners increasingly portray the opposition as being linked to Shiite power Iran and its proxies such as Lebanon's Hezbollah. No evidence exists of direct Iranian ties to the protests, but Tehran's state media gives extensive coverage to the crackdowns in Bahrain.
On the streets, the demonstrations have evolved from a general call for greater rights into a direct assault on the Western-backed monarchy. Chants of "Down with Hamad"—King Hamad bin Isa Al Khalifa—are now common.