 -- A little over a year ago, few people gave Germany's controversial, right-wing populist Alternative for Germany (AfD) party any chance of making a dent in German national elections. In recent months, the party suffered through several embarrassing internal spats and saw its polling numbers sink amid growing support for Chancellor Angela Merkel.

But AfD is now poised to become Germany’s third largest political party after Sunday's elections. Opinion polls show the AfD scoring as much as 12 percent of the vote on Election Day, allowing it to send dozens of lawmakers to national Parliament - or Bundestag - and potentially disrupting German politics.

If the predictions hold, it will be the first time since the end of World War II that a far-right party has attracted enough votes to enter Germany’s Parliament. And the strong showing means the AfD will be the biggest opposition party if Merkel's Christian Democratic Union (CDU) continues its governing coalition with the center-left Social Democratic Party (SPD).

"It's without question a significant achievement for a right-wing party when you view it historically,” said Karen Donfried, the president of the German Marshall Fund, referring to AfD. She said because of its Nazi history, German voters have usually rejected right-wing parties in elections.

“But this is a significant shift for the German political landscape,” she noted.

Founded in 2013 as an anti-European Union party, the AfD shifted its focus from the euro zone debt crisis to immigration after Merkel in 2015 opened the doors to over a million migrants, many fleeing war in the Middle East.

Since then, the party has increasingly found success by becoming the most visible anti-immigration party in Germany. It scored well in a series of regional elections thanks largely to a growing public anger over Merkel's welcoming policy toward refugees, particularly from Syria and elsewhere in the Arab world.

Gideon Botsch, a political scientist at the University of Potsdam just outside Berlin, said AfD's success is partly due to the disillusionment voters feel with Germany's established political parties.

“Many voters, especially on the right but also in the center, have felt that the two traditional parties have not addressed the issue of immigration and German cultural identity,” Botsch said. “And that has led them to consider voting for the AfD.”

The party's platform is staunchly anti-immigrant and opposes any welcoming of Muslims to Germany.

The AfD has called for sealing the European Union’s borders, instituting rigorous identity checks along Germany's national borders and setting up holding camps abroad to prevent migrants from leaving for Germany in the first place. The party also wants to deport anyone whose application for political asylum is rejected while encouraging foreigners to return to their home countries.

Party leaders believe the few migrants who are allowed to remain have a duty to fully integrate into German society, emphasizing the primacy of the German language and traditional German culture. Many of its top officials have outwardly rejected the idea that Islam is part of German society.

German Foreign Minister Sigmar Gabriel equated the party with the Nazis who ruled the country from 1933 to 1945, an insult rarely heard in national politics.

“If we’re unlucky, then these people will send a signal of dissatisfaction that will have terrible consequences,” Gabriel, a member of the Social Democrats, said in an interview with Internet provider t-online.de. “Then we will have real Nazis in the German Reichstag for the first time since the end of World War II.”

Justice Minister Heiko Maas warned that the AfD's religious, family, criminal and European policies are in clear violation of the German constitution. In an essay published in the Frankfurter Rundschau newspaper, he singled out a blanket ban on minarets - the towers on mosques from which the muezzin calls the faithful to prayer - which the AfD has promised to introduce.

Though the AfD platform says the party supports direct democracy, separation of state powers and the rule of law and order, throughout its short history, critics have accused individual members of promoting neo-Nazi ideas and using neo-Nazi language.

Earlier this month, the party was forced to defend its co-leader Alice Weidel following media reports that she had expressed racist views in a private email four years ago. Top AfD officials dismissed a report in the weekly Welt am Sonntag that quoted from an email Weidel allegedly sent to an acquaintance in which she claimed the government was trying to cause "civil war" by systematically flooding German cities with Arab and Roma migrants.

The AfD also developed a series of controversial campaign ads, including one showing the belly of a pregnant woman that says “New Germans? We'll make them ourselves.” Another ad declares “Burkas? We prefer bikinis.”

“In years past, these kinds of ads would turn off many voters in Germany,” Donfried said. “But this time around they seem to resonate with some voters and that’s been a problem for the two main politics parties.”