Donald Trump’s shoestring campaign has been plagued with reports of infighting and internal dysfunction from the start, but an MSNBC report out Monday details how those undermining factors could lead to “defeat” for the presumptive GOP nominee.

MSNBC reporters spoke with three Trump aides and two sources working closely alongside the campaign, all of whom spoke anonymously about the dysfunction that has come to characterize an operation in which Trump’s word is law.

“Bottom line, you can hire all the top people in the world, but to what end? Trump does what he wants,” a source close to the campaign said.

After the campaign seemed largely caught off guard by unsealed Trump University court documents last week that detailed craven allegations of defrauding students, Trump repudiated calls from staffers, donors and party officials to tone down his attacks on U.S. District Judge Gonzalo Curiel’s ethnicity, saying he didn’t want to look like he bowed to pressure.

“These are things that will defeat [us],” a Trump campaign source told MSNBC.

Many top campaign posts have remained unfilled, giving an outsized prominence to campaign manager Corey Lewandowski and spokeswoman Hope Hicks, both of whom travel with Trump. One internal source cautioned that Trump could lose the general election if he failed to flesh out his communications team.

MSNBC reported that internal tensions boiled over on the campaign trail again last week in California, as Lewandowski and Hicks repeatedly vetoed draft press releases to roll out new endorsements that top strategist Paul Manafort had lined up.

In typical Trump fashion, the real estate mogul slammed Katy Tur, one of the reporters on the story, on Twitter and defended his minimalist campaign infrastructure:

People like @KatyTurNBC report on my campaign, but have zero access. They say what they want without any knowledge.True of so much of media! — Donald J. Trump (@realDonaldTrump) June 6, 2016

Just like I have been able to spend far less money than others on the campaign and finish #1, so too should our country. We can be great! — Donald J. Trump (@realDonaldTrump) June 6, 2016

I am getting bad marks from certain pundits because I have a small campaign staff. But small is good, flexible, save money and number one! — Donald J. Trump (@realDonaldTrump) June 6, 2016

Read the full report from MSNBC.