Donald Trump literally could not explain the difference between a 'Muslim database' and the Nazis' treatment of Jews

The US appeared to finally think Donald Trump had crossed the line with the idea of registering all Muslims in the country in a database, and the presidential candidate has now backtracked.

In an interview with Yahoo! News on Thursday, the Republican presidential candidate was asked what he meant when he called for increased surveillance in the wake of the Paris terror attacks last week.

Trump told the reporter he remained open to the idea of registering US citizens who practice Islam in a database or require them to carry special identification papers:

We’re going to have to do things that we never did before. Some people are going to be upset about it, but I think that now everybody has the feeling that security is going to rule.

The comments and suggestion of a religion-filtered database drew criticism from all corners of the political spectrum. Other GOP candidates called the suggestion "abhorrent".

In a televised interview on Thursday night Trump doubled down on the idea, saying he would “absolutely” implement the plan.

And when asked by a reporter from NBC how it differed from the forced registration of Jews in Nazi Germany, Trump replied:

You tell me. You tell me.

But by Friday Trump had backed away from the idea, tweeting that it had originally been the Yahoo reporter's suggestion, rather than his own:

Now if he could just apologise for all his other divisive comments about Mexico, China, black people, poor people and women, that would be great.

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