The questions about Porter came on top of an earlier incident in which Kelly told reporters Tuesday that some of the young immigrants known as "Dreamers" who failed to seek legal protections under an Obama-era program were "too lazy to get off their asses," eliciting accusations that he was engaging in ugly stereotypes.
Kelly was brought into the White House in July after serving as secretary of Homeland Security. His predecessor, Reince Priebus, was seen as too weak to tame the White House's competing factions and gain the respect and confidence of President Donald Trump.
Those who know Trump well say he has valued Kelly's attempts to instill order, even though Trump has bristled at times over Kelly's desire to exert so much control over who sees and speaks with the president.
Last month, Kelly pushed Trump's limits when he told members of the Congressional Hispanic Caucus that the president's initial campaign promise of a solid continuous border wall was "uninformed" and that Mexico would not pay for it.
That, and similar comments to Fox News, prompted Trump to tweet defensively, "The Wall is the Wall, it has never changed or evolved from the first day I conceived of it," while conceding that "parts of it" would be transparent and other areas of the border with natural protections would not have any structure at all.
"Kelly, of course, has brought down an iron curtain, and I think the president likes the fact that it's more orderly," said Roger Stone, a longtime political adviser to Trump. But, Stone added that "having worked for Donald Trump for 40 years, at a certain point, he hates being left in the dark."
Stone called the Porter incident a "self-inflicted wound," though some of that criticism arises from Stone's view that Porter, a Harvard-educated former top Senate aide, is too closely tied to the Republican establishment.
Porter's resignation, and the fumbling White House response to it, also renewed attention to the White House's struggles to vet top employees -- one of the problems Kelly's supporters had suggested he could fix.
The earliest example of the vetting problem came with the naming of Michael Flynn as Trump's first national security adviser, despite known red flags that eventually led to his guilty plea on charges of lying to the FBI.
Just last week, Trump's appointee as head of the Centers for Disease Control and Prevention, Dr. Brenda Fitzgerald, resigned after Politico reported that she traded in tobacco stocks after taking the position. Tom Price, Trump's first secretary of Health and Human Services, was also accused of financial conflicts of interest. Anthony Scaramucci lasted just 10 days as Trump's communications director.