Donald Trump is a terrible champion for Republicans for many reasons—the recently released 2005 audio tape reveals the most egregious one. But his performance in Sunday’s debate in St. Louis against an ineffective Hillary Clinton demonstrated just how ill-equipped Trump is to challenge the weakest Democratic nominee in decades.

Despite Clinton giving him ample opportunity to make effective critiques of her and Barack Obama’s Democratic party, Trump instead missed opportunities and launched muddled attacks on his opponent. Trump’s tendency to make incomplete, stream-of-consciousness arguments that leave out important context served him poorly against a rival who was less adept than at the first presidential debate in parrying tough questions about her record.