Transcript for Why a former top Trump official has joined Joe Biden
We turn to our ABC news exclusive with the former top trump administration official who is joining forcing with Joe Biden to defeat Donald Trump. Miles Taylor was chief of staff at the department of homeland security. He now describes trump's presidency as, quote, terrifying and damaging to national security. We're going to talk to him live in a moment. First Cecilia Vega has the details on his stunning public break with the president. Good morning, Cecilia. Reporter: Stunning is right. Good morning. Many other former senior officials have gone public with their concerns about president trump's fitness for office. But this is the highest ranking former member of the administration to break ranks and endorse Joe Biden. He served as the trump administration's chief of staff in the department of homeland security for two years. And in this video released by Republican voters against trump miles Taylor says what he witnessed was terrifying. The president wanted to exploit the department of homeland security for his own political purposes. Reporter: He says president trump wanted to restart his family's separation policy at the border. He said he wanted to go further and have a deliberate policy of ripping children away from their parents to show those parents that they shouldn't come to the border in the first place. Reporter: And during those California wildfires, Taylor says the president told FEMA to cut off federal money to the state. He told us to stop giving money to people whose houses had burned down from a wildfire because he was so rageful that people in the state of California didn't support him. Reporter: The white house quick to fire back calling Taylor another creature of the D.C. Swamp who clearly just wants to cash in and from the president's son-in-law -- Look, miles was a nice kid. Clearly he wasn't up to the Reporter: He had choice words of his own calling the president unfocused saying he often wanted to do things that were illegal and in a "Washington post" Paup opponent wedding Taylor said, I can attest that the country is less secure as a result of the president's actions. Taylor also says the president bungled the coronavirus response with his, quote, cavalier disregard tore the seriousness of the threat. He says top officials have been regularly diverted from important work to chase, quote, absurd executive requests, LE Cecilia, thanks very much. Let's bring in miles Taylor right now. Thank you for joining us. Let's start out with criticisms, two, one you're trying to cash in on your public service and, number two, Jared Kushner is basically suggesting you were fired. What is your response? So, George, first and foremost, thanks for having me this morning. Look, I'll say this, as far as cashing in goes, in Donald Trump's Washington, there's no doubt that doing this is going to be tough for me representationally, professionally and it's certainly going to take a hit at my pocketbook. This has nothing to do with money this. Has to do with being honest about the president and putting country before party. As far as Jared goes, look, he and I got along quite well. My point is not to slander anyone else that served under the president. My focus is on the character of the president himself, which is what this election is going to be about. What were the circumstances of you leaving the administration? Yeah, so I left the administration on my own terms. I'll be frank. I left the administration because I got to a point where saying no was no longer enough. We were constantly in a position with the president where it's not that he would just tell us to do things that we would say are inappropriate, unethical or illegal, it's that he would continue to consistently tell us to do those same things. That was an enormous frustration and when I realized we weren't going to be able to pull him back from some of these impulses, it meant it was time to G I left of my own volition. The administration offered up a number of jobs that in any other administration would have been dream jobs for me, but at that point I was done and I needed to What do you say to those who say you should have left earlier. You were part of a family separation policy which you decry and publicly defended it and some Progressives are saying that right now. It's not good enough. You should have realized sooner this was not something that could be saved? Yeah, look, I'm glad you brought up family separation. That was actually a policy that was developed before I took on my role as deputy chief of staff in the department before becoming chief of staff. Attorney general sessions announced that a few days after I stepped into that role and before then I had been John Kelly's counterterrorism adviser so not focused on immigration. That said, family separation was a mistake. How that played out is a textbook example of government wrong, government gone wrong and a textbook example of how this president has created an environment where bad policy decisions get made. Now, fortunately a few months into that when we realized this was the train wreck that secretary Neilson had said behind the scenes this is going to be a train wreck, we got the white house to issue an executive order to put an end to the policy but here's the bigger concern, George, every single month I served in that administration, after we ended family separation, the president would come to us and say, not only he wanted to restart it, he wanted to double down and imcomplement a deliberate policy of ripping any kid apart from their parent has showed up at the border. Any kid at the border, that was stunning to me. Frankly it was one of the most disheartening and disgusting things I've ever experienced in public service and that's significantly contributing to me wanting to leave the administration. You said the president wanted to withhold FEMA disaster to California during the wildfires. What wildfires are you talking about? What happened with the aid? How was it communicate it had should be withheld? George, I wish I could tell you it was a one-time thing. It's not lost on me today we're talking about California wildfires because the first time we went through this was in 2018 and the president at the time would get into these phone rants with us, the secretary and myself about Jerry brown and how frustrated he was with brown and later Gavin Newsom because they didn't support him and he didn't feel like he had a base of supporters in California. So as wildfires were burning down houses in the state, the president basically said to us, I don't care, these people haven't done enough to deserve it. Cut off the money, in fact, that phone call that I referenced with FEMA officials, the secretary and I were so concerned because we didn't want our senior leadership to be exposed to how undisciplined and tumultuous the white house was because it made it harder for them to do their jobs so after that FEMA officials said, what do we do? The president has just told us to cut off money to people whose homes are burning down. Our answer was, we're not going to do it. Don't worry. We'll go back to the president but then, George, months after, again in January 2019 the president said he wanted to do it and again I think he tweeted about doing it. Fortunately it never happened. FEMA didn't follow through on it because I think they ultimately determined from the lawyers that a tweet wasn't an official order, but this is what we're talking about here. Having to play whac-a-mole with bad presidential decisions rather doing the work of governing. Do you expect more of your former colleagues to speak out now as we head into the final days of the campaign? So, I can't get into too much detail on it, George, but I'm going to tell you this, the president hasn't heard the last of us. In fact, me speaking out yesterday, you could think of it as an opening salvo and I'm not going to mention any other names yet, but the president can expect that in the coming weeks and months leading up to the election he is going to hear from more people who served in his administration and hear more of them give the same testimony I gave which is that he's ill-equipped to hold the office that he has and that a second term would be more dangerous than a first term. You'll hear that soon. Miles Taylor, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.