AMSTERDAM – Europe’s most controversial politician lives in a government safe house fitted with a panic room and guarded round-the-clock. A self-avowed foe of Islam who compared the Quran to Adolf Hitler’s “Mein Kampf” and called for a ban on Muslim immigrants, he travels by bulletproof car and rarely talks with journalists — choosing instead to funnel messages directly to supporters via Twitter and a personal blog.

But when Geert Wilders — dubbed “Mozart” for his bleached-blond bouffant hair — brought down the Dutch government last week in an extraordinary show of force by Europe’s resurgent far right, it wasn’t over his high-profile war on Islam. Instead, it was part of his emphasis on another belief that he and his Freedom Party now see as almost equally dangerous: an integrated Europe.

The rise of Wilders in the Netherlands is a cautionary tale for a continent in the midst of a debt crisis and where painful recessions, soaring unemployment and rising apathy among youths are fueling the strongest swell of support in decades for anti-immigrant nationalists.

For more than a generation, European political elites have sought to fuse the region by adopting the euro and a series of treaties that virtually erased national borders across a vast swath of the continent. But in the recent surge of the nationalist far right, and to a lesser extent the far left, European leaders are confronting not only a backlash to a united Europe, but also a troubling new hurdle in their efforts to resolve the 2 1/2-year-old debt crisis.

From France to Austria and Greece to Finland, the popularity of nationalists is growing as politicians such as Wilders tap into voter rage not only over the crisis, but also over the proposed cure being pushed by mighty Germany: harsh rounds of government cuts and difficult economic overhauls to restore investor confidence in Europe’s governments.

That austerity crusade is in danger of derailing, with even moderate leaders, including Italian Prime Minister Mario Monti, now saying that deep cuts are driving Europe’s economies into the ground.

Other critics, meanwhile, are arguing that the social pain from austerity is playing into the hands of politicians on the far right and left, who are portraying the cuts as part of a pattern that has seen European integration eat away at living standards across traditionally affluent Western Europe.

Even German Chancellor Angela Merkel has softened her rhetoric in recent days, playing up the need for policies that favor growth, although she continues to view fiscal discipline as a necessary tonic for Europe’s troubles. European Central Bank President Mario Draghi, also a fiscal hawk, called last week for a “growth compact,” and European leaders appear likely to work out modest policy changes in late June.

In the turmoil of the debt crisis, ideas long held by European radicals are going mainstream as centrist politicians seek to find their way in a sea of discontent.

n In France, for instance, Marine Le Pen of the National Front stunned observers by winning almost one out of every five votes in the first round of presidential elections a week ago on a platform that would have seen Paris withdraw from the euro zone and buck the German-led austerity drive.

Now on the ropes against his Socialist opponent, President Nicolas Sarkozy is currying favor with the far-right ahead of the decisive second vote, vowing to pull France out of the region’s open-borders treaty if negotiations under way to stem the tide of transplants from poorer quarters of Europe do not succeed in the months ahead.

n In crisis-devastated Greece, opinion polls ahead of parliamentary elections Sunday show that the once-obscure Golden Dawn — which wants to plant land mines on the country’s borders to protect against illegal immigrants — is on a surprise track to win seats.

n Austria’s far-right Freedom Party is running strong in opinion polls, and Finland’s nationalist True Finns party took a record 19 percent of the vote last year.

“It is now only a matter of time before one of these parties gets into power and tries to pull the rug out from under the euro,” said Maurice de Hond, a leading Dutch political pollster.

“If it doesn’t happen in the Netherlands, it will happen somewhere else in Europe. I am sure of it.”