Capping two days of often bitter debate on its platform and personnel, the Alternative for Germany appointed two chief candidates: 76-year-old Alexander Gauland, a hardline defector from Chancellor Angela Merkel's CDU, and Alice Weidel, 38, an openly lesbian former investment banker.
The party's telegenic co-leader Frauke Petry had already announced last week she would not join the campaign squad, following weeks of bitter infighting between populists and more radical, hard-right forces.
Weidel told cheering delegates that the AfD was the only party that could protect Germany's borders and ensure public security.
Referring to an attack on a Berlin Christmas market that claimed 12 lives committed by a failed asylum seeker, she called it a “scandal” that “in our country, Christian holidays have to be protected by police with machine guns and barriers for trucks”.
“As a woman I should be able to take the last train home in safety,” she added.
Earlier the party, now represented in 11 of Germany's 16 states, signed off on a programme that it hopes will pave the way for it to enter the national parliament for the first time in its four-year history.
It included calls to stop family unification of refugees already in Germany, strip immigrants convicted of “significant crimes” of their German passports, and declare Islam incompatible with German culture.
The AfD has seen its support plummet as the refugee influx to Germany has slowed in recent months, after Merkel let in more than one million asylum seekers since 2015.
Petry, a 41-year-old former chemist pregnant with her fifth child, was handed a stinging setback Saturday at the gathering in the western city of Cologne, which drew several thousand protesters and required a security detail of 4,000 police officers.
The around 600 delegates rejected Petry's call to adopt a more moderate-sounding “Realpolitik” programme intended to shut down the party's more extremist voices, including those who have attacked Germany's Holocaust remembrance culture.
The International Auschwitz Committee representing survivors of the Nazi death camp condemned the incendiary speeches in Cologne, which it said were aimed at “inciting panic, denouncing all other political forces and rejecting the cultural values that hold the culture of the republic together.”
Top-selling daily Bild called delegates' decision to not even debate her motion a “crushing blow” for Petry, who expressed bitterness on the sidelines of the meeting.
“I will step aside during the campaign, as that's what the party congress apparently wants,” Petry said, while pledging to remain party co-chairwoman “for now”.
“As long as the party is not willing to say in what direction it wants to go, a team will have to lead the campaign that can deal with this indecision better than I can.”
Acknowledging the damaging inner turmoil, Gauland expressed regret that Petry, who is very popular with the party's base, will not be front-and-centre on the campaign trail.
“It was a difficult party congress. Frauke Petry, I know it was a difficult day for you but we need you in the party,” he said to loud applause and chants of “Merkel must go”.
“From now on we are going to focus our attention on our political opponents.”
'Heading for a showdown'
Commentators said the party's unresolved power struggle further undermined its bid to surf the momentum of France's far-right presidential frontrunner Marine Le Pen, Donald Trump in the United States and the Brexit movement in Britain to electoral success in the September 24th vote.
Spiegel Online journalist Severin Weiland said it was now even “doubtful” whether the AfD would clear the five-percent hurdle to representation in the national parliament.
The daily Sueddeutsche Zeitung said that the rifts were less about the political goals of the party – the most successful right-wing populist outfit in Germany's post-war history – than personal ambition.
“The AfD is heading for a showdown that could end up breaking it apart,” it said.