On the day that Angela Merkel was being tipped to win the Nobel Peace Prize, her increasingly troublesome conservative ally Horst Seehofer unleashed a series of broadsides against the chancellor.

Following a meeting of Bavaria's cabinet Friday morning, State Premier Seehofer, who also heads the Christian Social Union, sister party to Merkel's Christian Democratic Union, threatened to take the federal government to the Constitutional Court if it did not agree to turn refugees back at the Austrian border as an "emergency measure."

"We are expressly of the opinion that immigration needs to be controlled and limited if we in Germany want to cope with it," Seehofer told reporters, alleging that Berlin was "endangering the states' independent capacity to act."

'Self-defense'

The statement backed up a pugnacious interview with Seehofer printed in Friday's edition of the "Bild" newspaper. Asked what Bavaria's new asylum reforms would entail, he began by referring to measures promoting "integration, education, and training" before lobbing his grenade: "There will come explicit measures of self-defense to limit immigration, such as turning back people at the Austrian border."

Though Seehofer conscientiously reiterated his support for Merkel in the rest of the interview - and was even forced to deny that he was out to topple her - the word "self-defense" set off alarm bells throughout the German media.

Some newspapers saw it as a moment of deliberate and hostile authoritarianism: "State self-defense: that is threatening with methods from the ideology of an absolute state," "Süddeutsche Zeitung" wrote. "The term self-defense signals that a politician wants to do something that isn't really legal, but which he thinks is necessary."

Attack on the rule of law

Refugees' rights groups were also quick to seize on the potential illegality that the word implied. "This is an attack on the rule of law," Pro Asyl said in a statement. "A short process at the borders has no legal basis. According to EU law, Germany is not allowed to turn back refugees to the neighoring state of Austria, only send them to the appropriate EU country."

Not only that, Pro Asyl added, "if refugees travel to Germany via Hungary or Austria, [Germany] must check whether a deportation to Hungary is even allowable under the European Convention on Human Rights."

But Stephan Dünnwald, of the Bavarian Refugee Council, said that it was legal to turn people back at the border without any asylum procedure - though such a measure harked back to rarely enforced international agreements. "It's never happened on this scale," he told DW.

Still, Dünnwald joined Pro Asyl in condemning Seehofer, comparing his policy to that of Hungary's right-wing prime minister, Viktor Orban. "He wants to be a little Orban," he said. "If Bavaria starts turning people away at the border, then it's obvious that Austria will do the same at the Hungarian border, and Hungary is already doing that with Serbia. It's a chain reaction and what we call Schengen will break apart - very quickly."

The death of 'Welcome Culture'?

Nevertheless, if "Bild" is to be believed, Seehofer has more of the German population on his side than Merkel does. Alongside the interview with the CSU leader, the newspaper - which launched its "We're Helping" campaign for migrants a few weeks ago - published the results of a poll inviting readers to choose between Merkel's "We'll manage it!" statement and Seehofer's "We can't take any more!" Ninety percent of the more than 344,000 respondents agreed with Seehofer.

Mirroring this, the anti-refugee rhetoric from right-wing parties has become increasingly hysterical in recent days. Also on Friday morning, the CSU's youth wing called for a migration cap of 250,000 per year, while the fringe Alternative for Germany party filed criminal charges against Angela Merkel for human trafficking because she opened the border to refugees in the summer.

But other polls have contradicted the dominant narrative that Germany's "Welcome Culture" of the summer is being eroded. According to the results of a Forsa poll published by "Der Spiegel" on Friday, 44 percent of Germans have actively helped refugees this year, either through donations or volunteer work.