Donald Trump. Carlos Barria/Getty Images

President Donald Trump said Monday that he announced his pardon of former Arizona Sheriff Joe Arpaio right as Hurricane Harvey was moving into southeast Texas because "I assumed the ratings would be far higher than they would be normally."

Standing alongside Finnish President Sauli Niinisto at a White House press conference, Trump was asked by Fox News reporter John Roberts what he would say to those, including Republicans, who had been critical of his pardoning Arpaio.

Arpaio, the former Maricopa County sheriff, was convicted of criminal contempt for ignoring a court order to stop racial profiling of Latinos.

"What do you say to your critics, some even in your own party, who say it was the wrong thing to do?" Roberts asked.

"Well a lot of people said it was the right thing to do, John," Trump said. "And actually, in the middle of a hurricane, even though it was a Friday evening, I assumed the ratings would be far higher than they would be normally. You know, the hurricane was just starting. And I put it out that we pardoned, as we say, Sheriff Joe."

"He's done a great job for the people of Arizona," Trump continued. "He's very strong on borders, very strong on illegal immigration. He is loved in Arizona. I thought he was treated unbelievably unfairly when they came down with their big decision to go get him right before the election voting started, as you know. And he lost in a fairly close election — he would've won the election, but they just hammered him before the election. I thought that was a very, very unfair thing to do."

Trump on pardoning Arpaio during Harvey: "I assumed the ratings would be far higher than they would be normally." https://t.co/4tMNoDKN4E — NBC News (@NBCNews) August 28, 2017

Trump added that when he mentioned Arpaio during his campaign rally in Arizona last week, "the place went absolutely crazy."

The president then rattled off a list of controversial pardons and commutations handed down by recent presidents, appearing to equate his pardon of Arpaio with some of the most ridiculed pardons in recent decades.

Trump mentioned Marc Rich, the businessman who was convicted of tax evasion and for making oil deals with Iran during the hostage crisis. President Bill Clinton pardoned Rich during his last day in office. Trump also noted the commutation to Chelsea Manning, the soldier who disclosed confidential information to WikiLeaks. Manning served seven years in federal prison before President Barack Obama commuted her sentence shortly before his time in office was complete.

Trump incorrectly suggested that Manning was "perhaps" pardoned by Obama.

Trump did not provide any legal rationale for why Arpaio deserved a pardon, but he did call the 85-year-old a "great law-enforcement person" and "someone who's won many, many elections."

"Sheriff Joe is a patriot," Trump said. "Sheriff Joe loves our country. Sheriff Joe protected our borders."

"I stand by my pardon of Sheriff Joe," Trump added. "And I think the people of Arizona who really knew him best would agree with me."

Trump's Friday-night pardon of Arpaio was met with widespread ridicule on both sides of the aisle, including from both of Arizona's Republican senators, John McCain and Jeff Flake.

Arpaio became a notorious figure over the more than two decades he spent leading the sheriff's office. He is perhaps best known for keeping inmates in a "tent city" jail under inhumane conditions. He once called the sweltering open-air facility a "concentration camp."

An outspoken Trump supporter, Arpaio was also one of the leading figures of the "birther" movement, which sought to delegitimize Obama by claiming he was not born in the US.

The Washington Post reported this weekend that Trump asked Attorney General Jeff Sessions months ago whether dropping the case against Arpaio was a possibility, to which Sessions said it would be inappropriate. He did say then, though, that a pardon could be granted, a move about which Trump was reportedly "gung-ho."