Sarah Kendzior is a St. Louis, Mo.-based commentator who writes about politics, the economy and media.

Since 2015, Donald Trump has been running a dual campaign: a run for the presidency, and a promotion for his businesses, uniting both under the gleaming gold banner of TRUMP. He touted his financial success as a rationalization for his candidacy, and used his candidacy as an excuse to hawk his products – most notably during his "birther" press conference, a Trump hotel infomercial concluding with a few minutes of racist excuses and lies.

Trump has wavered on many policy issues, but never on his own glory. Trump as brand stood in where facts failed to materialize. "Believe me," Trump assured Americans, without giving them a reason. He offered no proof of even basic financial acumen like tax returns. His lies and omissions did little to puncture his persona, which, buoyed by a complicit media, was presented as powerful and persuasive.

Story continues below advertisement

Related: Clinton-Trump debate: What you missed and what's next

Ibbitson: Trump as president? No reasonable voter could want that after the debate

Doyle: Trump defeated by the most basic rules of television

Last night, Hillary Clinton, the daughter of a drape maker, revealed the man behind the curtain. Combining the personal with the political, she hit Trump where it hurt – his brand, revealed to be as bankrupt as the businesses he bottomed out.

Before last night, Trump had never been confronted directly by an adversary for a sustained period of time. He had appeared before cheering crowds and chatted with sycophants, but dodged or banned any journalist who challenged him. Unlike, for example, Sarah Palin and Katie Couric in 2008, Trump never had an extended interview with an objective party. At the first presidential debate, it was painfully evident why.

Clinton's brand-destroying strategy emerged early on, when the two candidates were asked about the economy. As Trump lied that he was given a "very small amount" by his father – in reality, it was millions – Clinton noted not only his wealth but his reluctance to spread it. She ticked off a list of workers who he refused to pay, adding that she was grateful that her father was not among them.

Trump's attempt to present himself as someone who understood American economic pain crumbled when he was outed as a man who caused it. Clinton debunked not only Trump's origin story, but the ethics of his business practices and, in turn, the ethics of his candidacy. He never recovered.

Story continues below advertisement

Trump not only failed to deny that he fleeced workers; he implied they deserved it. When the issue of his tax returns was raised, Trump lied about why he couldn't release them, citing an audit – which does not prohibit release – and stating that not paying taxes "makes me smart" and is "good business."

Clinton gave names to these unethical practices: "the Trump loophole" and "Trumped up, trickle-down economics." Trump, who has spent his campaign devising nicknames for rivals, faltered when his own beloved name was cast in a disparaging light. Lauded by some for his potential to shake things up, Trump was now inextricably tied with shaking people down.

In a classic use of projection, Trump went on to accuse numerous foreign parties, including NATO members, of not paying their share – a claim which fell flat not only because Trump freely admitted he refused to pay his own share, but because his answers revealed his bizarre views of geopolitics.

When asked about Russia, Trump avoided the question. When pressed on ISIS, he gave baffling responses, including a claim that Clinton, 68, had been fighting ISIS her entire adult life – that is, decades before ISIS existed. His responses on cybersecurity ranged from "The computer aspect of cyber is very, very tough" to speculating that America is under siege from "somebody sitting on their bed who weighs 400 pounds."

But it was the decimation of the Trump brand that seemed to bother him most. Trump complained at the end of the debate that Clinton had run "very mean" ads about him – neglecting to mention that these ads consist largely of Trump's own words. Clinton responded with yet another personal tale of a woman Trump had insulted and degraded. She forced him to see himself as many others see him: as an abuser, a liar, and a failure.

In the end, Clinton was not Trump's greatest enemy. "I alone can fix it," Trump famously proclaimed at the GOP convention. Last night, Trump revealed he alone could destroy it, too.