"Today, Bernie Sanders will be endorsing one of the most pro-war, pro-Wall Street and pro-offshoring candidates in the history of the Democratic Party," said Stephen Miller, a Trump senior policy advisor, in a statement. "The candidate who ran against special interests is endorsing the candidate who embodies special interests."
Sanders, the senator from Vermont who energized many Democratic and independent voters with his candidacy, endorsed Clinton in New Hampshire on Tuesday. Trump, the presumptive Republican nominee, has aimed to court Sanders supporters, many of whom perceive the political system as stacked in favor of elites. Some see Clinton as the embodiment of that system.
Trump commented on Twitter, saying that Sanders' endorsement of Clinton has angered many Sanders' supporters and that he was not being "true to himself."
Sanders has previously criticized Clinton's ties to Wall Street and her support of international trade deals.
The Vermont senator responded on Twitter to Trump's criticism.