"I don't think you've seen him go down there and campaign for him, I don't think you've seen him issue an endorsement," Short told ABC News Chief Anchor George Stephanopoulos on "This Week" Sunday. "I think he thinks it's best for the people of Alabama to make that decision."
The first round of allegations against Moore were published in the Washington Post on Nov. 9 while Trump was overseas on his 13-day Asia tour. White House press secretary Sarah Sanders said at the time that Trump believes "if these allegations are true, Judge Moore will do the right thing and step aside."
Trump has refrained from further commenting on the allegations against Moore, although reporters have repeatedly shouted questions at him about the GOP Senate candidate since the president returned to the U.S. from Asia.
On "This Week" Sunday, Stephanopoulos repeatedly pressed Short about whether Trump believes the women accusing Moore of sexual misconduct or inappropriate behavior.
"I'm asking you a direct question on behalf of the president," Stephanopoulos said. "You work for the president. Does the president believe the women or not?"
"If he did not believe that the women's accusations were credible, he would be down campaigning for Roy Moore. He has not done that. He has concerns about the accusations, but he is also concerned that these accusations are 38 years old," Short said. "Roy Moore has been in public service for decades, and the accusations did not arise until a month before election."
"We do have serious questions about the allegations. And the president has raised those and it's one of the reasons why he has not gone down to campaign for Roy Moore," he said.
If Moore wins, Short said it will be up to the Senate to decide if it wants to take action, such as to start an ethics investigation into the allegations against him.
"I do think, George, that several instances have happened in the past when senators have been removed from office," Short said. "Typically those instances, though, are when [senators] ... had abuses [while] in office. I'm not familiar with the Senate making the decision that all the public information was out there and the people made an election, and then the Senate decides to overturn the wisdom of the people of the state," Short said.
"Having said that, we think that the people of Alabama will have a lot of wisdom in making the right decision come December 12," Short said.