He had access to classified materials.
Shah called the assault allegations "serious and disturbing", ramping up the White House's reaction after defending Porter much of Wednesday. Reports suggested that Chief of Staff John Kelly knew about these allegations and protected Porter.
Shah also noted that President Trump was "saddened" by the matter. "It was not completed, and Rob Porter has since resigned", he said.
President Trump was not aware of Porter's security clearance status, Shah said, and didn't find out about the allegations against Porter until Tuesday evening.
Kelly apparently did not listen to Portman's two ex-wives who tell harrowing stories about being victims of extreme physical and emotional abuse.
Kelly's handling of the situation was causing some in Washington to question his political judgment and management skills.
The president, for his part, has not signalled to allies that he is on the verge of making a change.
It's hard to see why Kelly, who was supposed to be the disciplined adult in this administration, would cover for Porter.
"My commitment to public service speaks for itself".
"We do take allegations of misconduct, of domestic violence, other issues like that very seriously", he said. "But this was the Rob Porter that I and many others have dealt with, that Sarah dealt with, that other officials, including the chief of staff, have dealt with".
Previously, U.S. Ambassador to the UN Nikki Haley listed Shah among the top Indian American performers working under the Trump administration.
Until hours before the Harvard graduate left his post, the White House was praising him as an upstanding and integral member of staff. He was bombarded by questions on a senior White House advisor's sudden exit.
"If John Kelly is covering this up, he needs to be held accountable, no if, ands or buts about it".
Nadler added, "They don't really care about domestic violence". (Vanity Fair has a lovely picture that sums up the entire problem.) He has to go now, too.
Eventually, more rational heads prevailed.
A deputy chief of staff, Joe Hagin, was concerned that Rob Porter hadn't yet passed a background check more than a year into his tenure and briefed his boss, Mr Kelly, it was said. But new reports surfaced this week claiming that Porter physically abused his two ex-wives, one of whom filed an emergency protective order against him.
However, Shah also asserted (below) that Kelly only became "fully aware" of the accusations against Porter on Wednesday. Shah said his last day was Thursday and that he cleaned out his desk Thursday morning.
He denied both of the ex-wives' allegations.
"I shared with them the details of my marriage the same as I have been in the interviews and articles that have come out", she added. When you're a chief of staff, you spend a lot of time with this president.
But that semblance of confidence has been eroded.
Less than a week ago, he called the young immigrants known as "dreamers" were just "too lazy to get off their asses".