Latest Tweak in Donald Trump’s Proposed Muslim Ban Raises More Questions

— -- The latest adjustment in Donald Trump's proposed temporary ban on Muslims' entering the United States comes in relation to which Muslims would be affected.

Some kind of ban on Muslims has been the centerpiece of Trump's presidential campaign, but his description of it has changed since he introduced the concept in December.

It started as a temporary "total and complete shutdown of Muslims entering the United States"; now it would be limited to a ban focusing on "terrorist" countries.

But his aides have repeatedly denied that this represents a shift in policy.

Trump spokeswoman Katrina Pierson rejects the notion that Trump targeted all Muslims from the beginning, even though he did. And the new language was just a matter of "adding specifics to clarify his position," she said during a Monday appearance on CNN.

"There's been no change. Mr. Trump still wants to stop individuals from coming into their country who cannot be vetted," Pierson said.

When it comes to specifics, however, several key details about the supposed clarifications remain to be seen. The Trump campaign has not responded to ABC News' repeated requests to explain how he would determine the "terrorist" countries.

During a trip to Scotland to visit one of his golf courses last week, Trump said it "wouldn't bother me" if Muslims from Scotland went to the United States.

His son Eric Trump weighed in during an appearance on Fox News on Monday, saying he thinks the biggest difference is that someone from Scotland who is Muslim could be more easily vetted than those from other countries.

Eric Trump went on to say that the problem with letting in Muslims from places like Syria is that "they don't have files or documents." Such a clarification had never been made by a Trump associate about the proposed ban before this week.

Donald Trump previously said there would be some exceptions to the ban. He told The Washington Post in December that foreign leaders and athletes headed to the United States for competitions would be exempt.

He also said during a Wisconsin town hall in March that his "very rich" Muslim friends wouldn't have a problem getting into the United States.

"They'll come in," he said. "And you'll have exceptions."