"I think what a number of us have been concerned about is a pattern of laxity with regard to details," Sanford told CNN in an interview, explaining that details are critical to good governance, one day after he was part of a group meeting with the presumptive Republican presidential candidate. "It is the details that really matter in impacting people's lives. It is the details that matter frankly in any legislative negotiation."
The South Carolinian lawmaker, who has been critic of Trump, said that lack of respect for details could make it difficult for the businessman to be a successful president.
"I wasn't particularly impressed," Sanford told reporters after Thursday's meeting at an event. "I think it was the normal stream of consciousness that's long on hyperbole and short on facts. At one point there was mentioned -- somebody asked about, you know, Article I powers and what would you do to protect them and you know, I think his response was 'I want to protect Article I, Article II, Article XII -- go down the list.' As we both know there is no Article XII."
Trump's answer came in response to a question from a House Republican about whether Trump as president would defend the prerogatives of Congress that are laid out in Article I of the Constitution. The issue is highly important to lawmakers who are frustrated by the powers of the presidency, which are defined in Article II of the Constitution but that have expanded in recent years by the increased use of executive authority.
There are a total of just seven articles to the Constitution although there are many more amendments to the founding document, which could be what Trump was referring to accidentally.
The Trump campaign did not immediately respond to CNN for a comment about the apparent gaffe in the meeting or Sanford's concerns.
When Trump made his comments "a number of people looked around at each other at that point with a little bit of a quizzical or curious eye," Sanford told CNN Friday.
Sanford, who still hasn't decided if he will back his party's presumptive nominee, acknowledged Trump has successfully connected with voters even as he glosses over the minutia of governing.
"I would say we all love broad sweeping statements. They're pleasant. At times they're amusing, at times they're interesting, but in terms of making a difference in people's lives, it's the details that matter," Sanford said.
Sanford also defended Trump.
While "there seems to be a deliberate lack of detail" from the candidate, there is not "malfeasance" -- as Sanford said was on display Thursday in a House committee that was examining Democratic presidential candidate Hillary Clinton's email usage while running the State Department.
"What we're left with is a Faustian choice between malfeasance and very callous disregard for details," Sanford said.
In the meeting with House Republicans, Trump repeatedly stressed the importance of a Republican winning the White House because of the balance of power on the Supreme Court. In the end, Sanford suggested that issue might be enough to tilt him to vote for Trump, something initially he didn't think he would do.