Richard Haass, the president of the nonpartisan Council on Foreign Relations, also told CNN's Erin Burnett
on "OutFront" that Secretary of State Rex Tillerson is "essentially home alone" at the State Department and that it could have dangerous consequences for US foreign policy.
Asked if the world is less safe than it was one month ago, Haass, the State Department's director of policy planning under former President George W. Bush, said "the one thing I think the administration did that may have made the United States and the world less safe was its position dealing with refugees and the whole Homeland Security issue."
Haass added, "By moving away from so many established positions, we've created real doubts in the minds of our friends and allies about whether we are dependable, whether we're reliable, whether what has been the case remains the case."
He continued: "So I don't think it's that we're in the short run less safe, but what worries me is we're setting in motion dynamics and trends that over months or years will reduce US influence and will mean that a lot of traditional friends and allies increasingly go their own way."
CNN has reached out to the White House for comment.
Haass also said Tillerson is dealing with a "lack of support" at the State Department and was "essentially home alone."
"There's no staff, he wasn't able to get the deputy he wanted, so that's one issue," he said.
Haass made the comment when asked about Tillerson staying at a sanitarium 30 minutes away from other world leaders who are attending the G-20 summit in Germany.
He said President Donald Trump must show that the "secretary of state speaks for him, that the two of them -- that there is no daylight between them."
"No secretary of state can be successful if the world does not think he speaks and speaks authoritatively for the president," Haass cautioned. "Let me just say every day that goes by with this sort of thing happening, it begins to create doubts, and doubts are poisonous for the ability of a secretary of state to be effective."
Haass also ruled out talk of him becoming deputy secretary of state for Trump, saying he is not interested in the position and that there are many areas where "I'm not in sufficient alignment with this president and this administration so far to accept a senior position."