(WASHINGTON)-- Republican presidential candidate Nikki Haley on Sunday wouldn't definitively say if she'll back primary rival Donald Trump in the general election but stressed that she's staying in the race against him because of what she called his unfitness for office.
"I am running against him for a reason. ... The last thing on my mind is who I'm going to support. The only thing on my mind is how we're going to win this," Haley told ABC News "This Week" co-anchor Jonathan Karl when he asked if she would stick with the pledge she previously signed to support whomever the party's eventual nominee is even as she has become vocally critical of Trump.
"I'm not going anywhere," Haley added. "We’re going to do this for the long haul and we’re going to finish it."
Noting that she'd already signed the party's pledge, Karl pressed Haley, "Does that mean you will not support him if he’s the Republican nominee?"
"Y’all can talk about support later. Right now you can ask him if he’s going to support me when I'm the nominee," she said.
"Do you think he would [support you]?" Karl asked.
"Do you think he would?" Haley asked back, laughing. "I highly doubt it."
Appearing on "This Week," the former South Carolina governor repeated her criticism of Trump as too unstable to lead the U.S. at a time of crises elsewhere, like in the Middle East and Europe.
"This is not the time to talk about America hiding in a bubble and not doing anything with the rest of the world," she said.
She called out Trump's silence in the wake of the death of the imprisoned Russian opposition leader Alexei Navalny -- suggesting that it shows how he really feels about Russian President Vladimir Putin.
"Either he sides with Putin and thinks it's cool that Putin killed one of his political opponents, or he just doesn't think it's that big of a deal," Haley told Karl. "Either one of those is concerning. Either one of those is a problem."
Haley and other leading American politicians, including President Joe Biden, have said Putin is to blame for Navalny's death, which the Kremlin denies.
Rather than comment on Navalny, Trump on social media vowed to "bring Peace, Prosperity, and Stability" if he is elected again.
Haley, who served as Trump's U.N. ambassador, also accused the former president of emboldening Putin after saying earlier this month that he would "encourage" Russia to "to do whatever the hell they want" to U.S. allies who don't spend enough on their defense.
"That's bone-chilling because all he did in that one moment was empower Putin," Haley said on "This Week."
"We need to remind the American people that Vladimir Putin is not our friend. Vladimir Putin is not cool," Haley said. "This is not someone we want to associate with. This is not someone that we want to be friends with. This is not someone that we can trust."
Standing against Putin also means standing with "the Russian people who believe Navalny was really talking for them," Haley said -- calling Navalny a "hero" -- and standing with Ukraine in fighting against Russia's invasion.
But pressed by Karl on Ukraine aid legislation that is stalled in Congress, with Republican Speaker of the House Mike Johnson refusing to bring it up for a vote over a dispute about border politics, Haley turned to President Joe Biden.
"Well, I think first you have to talk about what should Joe Biden be doing," Haley said. "The reason you're seeing America become more isolationist is at no point has Joe Biden had a conversation with the American people about why Ukraine is important."
"It's not Biden that is stopping that aid in Congress. It's Republicans," Karl said back, noting Biden's earlier visit to the war-torn country and the multiple prime-time addresses to the nation he's given on the issue.
"This is not the time to pick which side is right or wrong," Haley replied, adding that Biden "needs to be speaking more to the American people about what this package means" while contending that Congress was also "failing" and "needs to do their job and make sure that they go and do everything they can for national security."
"They're making this sound like you have to choose between Ukraine and Israel and securing the border. They are lying to the American people. That's a false premise. We can do both," she said.
Karl cited Trump's yearslong skepticism about NATO and asked if Haley was concerned that, if elected again, Trump "could actually threaten the NATO alliance?"
Haley said that she was "worried about a lot of things if Trump is reelected," including that, calling the post-World War II alliance "a 75-year success story" in preventing widespread conflict.
"This is not the time to leave an alliance. This is not the time to side with a thug and not side with our friends who stood with us after 9/11," Haley said. "We have to make sure that we stand firm because when we stand firm with our friends, our enemies stay on their heels."
Amid the controversy over Trump's latest NATO remarks, a campaign spokesperson defended him by saying he "got our allies to increase their NATO spending by demanding they pay up. ... When you don't pay your defense spending you can't be surprised that you get more war."
Haley on Sunday also criticized Trump's push to install new leadership at the Republican National Committee, including one of his top aides and his daughter-in-law, Lara Trump.
While a party's presidential nominees historically shape the party around them, Donald Trump is still in a primary race against Haley, though he's won every state so far.
"The part I worry about is the RNC is now going to be the piggy bank for Trump's legal fees," Haley said on "This Week," arguing that such a move would impact races across the country.
Lara Trump has said that under new leaders, "Every single penny will go to the No. 1 and the only job of the RNC, that is electing Donald J. Trump as president of the United States."
"You can hang up winning the House and the Senate or having any resources for us to win any other races if all they're doing is thinking about how they're going to pay his court season," Haley said on Sunday.
She repeated her pitch to voters: "We need a new generational leader that's not distracted by court cases, that's not filled with vengeance towards our enemies, that's not in the drama."