Speaking to Idea, a local evangelical Christian news outlet, back in February, Brinkhaus said he didn't see any problem with a Muslim being Germany's leader.
"Why not, if they're a good politician, and they represent our values and our political views?" the politician asked. "The CDU is not a religious community – that is what distinguishes us from the Catholic Church," he added.
Brinkhaus emphasised that with the decline in religiosity among CDU voters, career opportunities were opening up for non-Christians. "Therefore, Muslims who share our values – human dignity, personal responsibility, solidarity and the Basic Law are welcome to join the CDU," he said.
The story prompted many members of his own party to attack Brinkhaus.
"For the love of God, I can't believe Ralph Brinkhaus said that," the CDU chief in the state of Mecklenburg-Western Pomerania told Bild. "No, I can't believe it."
Elisabeth Motschmann, CDU lawmaker and member of the party's executive board, challenged Brinkhaus's sentiments about the compatibility of Islamic values with those of the CDU. "The values of Islam are very different from our values – for example, when it comes to questions of equal rights for men and women," she said, adding that all the talk of Muslim chancellors was "unsettling" to voters.
Eberhard Gienger, another CDU MP, also disagreed with Brinkhaus, telling Bild that Islamic values including Sharia law, polygamy, attitudes toward homosexuals, and "even the position of women" in society were incompatible with those of the party.
Karin Prien, CDU Education Minister in the state of Schleswig-Holstein, similarly defended him, noting that "of course, a Muslim Christian Democrat, a Hindu or an atheist could run for Chancellor."
Germany's Social Democratic Party (SPD), who work alongside the CDU in a coalition government, dismissed the scandal altogether, with SPD deputy chief Ralf Stegner telling Saarbrucker Zeitung that "all these identity debates are conducted only in the CDU," and that they have "nothing to do with" Germany's "real problems".
'C' in CDU Stands for 'Christian'
As might be expected, Brinkhaus's contentious remarks also resulted in a massive debate online.
In a scathing op-ed, Bild deputy editor-in-chief Daniel Bocking wrote that if the CDU wants to accept a Muslim chancellor, it should delete the 'C' from its name.
"The CDU is not called the 'Good Political Party' or the 'Values and Views' Party, but the 'Christian Democratic Union'. The word 'Christian' represents not only a moral value, but also faith – in Jesus Christ. This may not sound hip, but that's the way it is," Bocking wrote. "And every Muslim would agree: although Jesus is considered a prophet in Islam, Muslims do not share Christians' faith in him as the Saviour and Son of God, which is the core of Christianity," he added.
Others failed to see the problem, or even praising Brinkhaus for his refreshing tone. "Only when we no longer think about which denomination or religion a candidate belongs to will we develop further," one user argued.