In the 1970s, when most Asians lived on farms, ideologues fought their battles in mountains and jungles across Southeast Asia. Now, after some of the largest demographic changes in history, radicals can recruit massive followings in cities such as Bangkok with millions of disaffected laborers who no longer have farms to return to.

When I first lived in Bangkok in 1987, the city of 6 million was dominated by Chinese-Thai business elites and Thai officials with fair skin and links to the monarchy. Farmers in Isaan in the northeast seemed to live in another century, plowing parched rice paddies with water buffaloes. Youth flocked to Bangkok for a flashier life.

After two decades of migration from northern provinces which doubled Bangkok’s population, these poor dark-skinned laborers — and their city-bred offspring — have essentially held the government hostage and pushed it to call for November elections a year ahead of schedule.

This demographic time bomb also exists in Shanghai, Hong Kong, Jakarta, Ho Chi Minh City (Saigon), Manila and other cities with huge migrant populations. If Thailand’s red shirt uprising is a revolution of rising expectations among the servant class, then migrant laborers elsewhere might also demand a greater share of political power.

In the case of Bangkok, a new generation of insurgents — born up-country, raised in the city — managed to take over central Bangkok in a dramatic display of force that startled visitors and most Thais as well. Dubbed “the Bamboo Fortress,” their protest site struck me as something kids would make if given free reign over a city; indeed, kids were among the protesters who built up barricades out of tires, bamboo staves and razor wire. Occupying a swath of central Bangkok roughly the size of the Forbidden City in Beijing or Shibuya in Tokyo, the “Red Zone” also drew comparisons with the Green Zone in Baghdad and Palestinian enclaves in Israel because of its maze of checkpoints manned by surly guys in black and red who evoked fears of the Khmer Rouge takeover of Cambodia in 1975.

Unlike previous conflicts in remote border areas, this urban rebellion has been happening outside the balconies of Bangkok bloggers and the windows of commuters, Japanese expats and tourists on the Skytrain. Lacking direct contact with protesters, many in the Thai media have mislabeled them off-duty farmers; in fact, many live and work in Bangkok and are able to quickly pad the size of crowds wherever protests occur.

The red shirts, who are used to taking sweaty buses or whiny two-stroke motorcycles to low-paying jobs with no benefits, have no qualms about causing inconvenience to white-collar employees and middle-class shoppers addicted to their air-conditioned cars.

Their protests — first near the backpacker mecca of Khao San Road, and then near Siam Square — have superimposed their rural-rooted culture into core urban areas. With maw-ram music and frying pans burning chilies, their protests resemble up-country temple festivals, with street vendors selling red rambutans, red sausages and almost anything else red.

While some enjoy the chance to stroll through central Bangkok without traffic jams and noxious fumes, many Bangkokians and royalist “yellow shirts,” on the other hand, are sick of them, and angry at Prime Minister Abhisit Vejjajiva for not evicting them by force. But the problem is, even if the reds surrender now, they could easily re-emerge to take over another site of Bangkok, such as Suwannabhumi airport, as the yellows did two years ago.

Known for decades for Buddhist tolerance and political apathy, Thailand’s transformation into a highly politicized and polarized society is a shock for many frequent visitors. Rallied by almost nonstop speeches and comments on TV and radio, the lower classes from rural provinces as well as Bangkok are no longer afraid to spout their anger at Thailand’s elites, who they say have made them prai(slaves). I hear this in every taxi, restaurant and shop in Bangkok — far beyond the protest areas.

Unlike previous uprisings in Bangkok led by students in 1976 and the middle class in 1992, the red shirts who have been sleeping overnight in the fortress are mainly seniors and women with kids — the type of ordinary people who gave Thailand it’s reputation as the Land of Smiles. Often lacking formal education, people such as Euang, a Bangkok housewife who left her kids with relatives in order to stay in the Red Zone, and Nee, a Bangkok mother who sells clothing to protesters, are happy to talk about ideology and injustice.

Their calls for change increasingly echo across Thai society and the colorful expat community. In a mix that only makes sense to Thai insiders, many say they are pro-red shirt, pro-Abhisit, pro-King Bhumipol, anti-Thaksin, anti-military corruption, and anti-yellow shirt leader Gen. Chamlong Srimuang.

With a strong following everywhere but southern Thailand, the reds could win the next election by sweeping the north and winning half of Bangkok, as former ousted Prime Minister Thaksin Shinawatra once did. Even if they lose the election, their protests will continue until they finally get their say and their way.

With millions of former farmers now in cities to stay, entrenched elites from Bangkok to Beijing to Mumbai will have to make room for them in government. Otherwise, given the ready supply of bamboo across Asia, more fortresses could go up in the cities of the region.