Turkish Prime Minister Tayyip Erdogan has blamed an outbreak of protests against his government on "looters" and "bums" and extremists who, he says, are "arm-in-arm with terrorism." He also accused demonstrators of stirring up unrest with "lies" spread on Twitter. But activists and political experts say his defiant reaction is what transformed a peaceful vigil to save a park's sycamore trees into five days of broadening and increasingly volatile protests across the country.

The protests erupted after police used tear gas and water cannons to disperse crowds — initially just 50 or so people — that gathered in one of Istanbul's last remaining green spaces to protest plans to remove the square's trees and put buildings in their place. The government quickly withdrew the riot police, but on Monday night a protester was killed at a rally. On Tuesday, Deputy Prime Minister Bulent Arinc, who took charge after Erdogan left on a visit to North Africa on Monday, apologized for the crackdown, calling it excessive and just plain wrong. The government has also promised an investigation — but many argue that the damage is done.

The government's violent response has triggered an eruption of anger at what Erdogan's critics say is his government's increasingly authoritarian excess. The first protesters were, literally, tree huggers. And the tens of thousands now raging in the streets are chanting "Down with the dictator," "Tayyip, resign," and "Unite against fascism." As The Week's Keith Wagstaff points out, it would be an exaggeration to call this an Arab Spring protest movement like the ones in Egypt and other countries in the region — Turkey already is a democracy. But it's still a very real setback for Erdogan.

The public anger is a sign that more and more Turks have come to believe that Erdogan's governing Justice and Development Party has gone too far with Islamist policies — including laws like one passed last week limiting alcohol sales — violating modern Turkey's founding principles of secular democracy, established by Kemal Ataturk. Making matters worse, Erdogan has vowed to go forward with the development plans in Taksim Square that were the target of the initial protest.

The prime minister's attitude is hardly surprising, some analysts say. Other Islamist leaders have had exactly the same arrogant reaction to their opponents' views, Shadi Hamid, director of research at the Brookings Doha Center, tells USA Today. Muslim conservatives who have taken power recently across the Arab world believe that winning elections gives them a mandate to enact their policies unchallenged, Hamid says. "There's less of an idea of consensus building," he says.

This could prove a costly misstep for Erdogan. As Murak Yetkin notes in Turkey's Hurriyet Daily, the scene unfolding in the country's streets has diminished Erdogan's standing, with potentially significant political repercussions for the prime minister and his party. "To cut the story short," says Yetkin, "the Taksim wave of protests has turned into the first public defeat of the almighty image of Prime Minister Tayyip Erdogan, and by Turkish people themselves."

Yet, Erdogan still has his power base, including the Muslim conservatives who have helped his party win elections, and he still has fans thanks to Turkey's healthy economy. The secular opposition also doesn't appear to be able to offer up a credible alternative. Stratfor notes, however, that Erdogan's dwindling appeal could force him to scale down his ambitions. For example, Stratfor says, the unrest doesn't bode well for the prime minister's plans for a constitutional referendum beefing up presidential powers, a position Erdogan hopes will allow him to continue running the country when his term as prime minister ends in 2015. And that's just the beginning of his new headaches:

Turkey is pursuing a highly ambitious agenda abroad, from negotiating peace with Kurdish militants and developing oil pipelines in Iraqi Kurdistan to trying to fend off Syrian-backed militant attacks. Turkey was already highly constrained in pursuing these foreign policy goals, but they will take second place to Turkey's growing political distractions at home as Erdogan prioritizes the growing domestic challenges and as foreign adversaries such as Syria try to take advantage of preoccupied Turkish security forces to try to sponsor more attacks inside Turkey. [Stratfor]