Left-wing darling Elizabeth Warren made her first appearance with Hillary Clinton on the presidential campaign trail this week, and her stock as a potential vice presidential pick immediately ticked up.

Speaking in Cincinnati, Ohio — a state hard hit by America’s manufacturing crisis — the senator from Massachusetts ferociously tore into Republican presidential candidate Donald Trump. She called him a “small, insecure money-grubber who fights for no one but himself,” drawing Trump’s fury on Twitter while effectively neutralizing some of his effectiveness as the populist candidate standing up for the little guy.

Warren’s emergence as Trump’s chief public antagonist is but another example of how both parties are adopting an anti-establishment tone to reach increasingly bitter and angry voters. Following British voters’ decision to leave the European Union last week, Trump this week doubled down on his criticism of US free trade deals, even going to war with the reliably pro-Republican Chamber of Commerce.

Speaking in western Pennsylvania on June 28, Trump vowed to rip up international trade deals and start an unrelenting offensive against Chinese economic practices, framing his contest with Clinton as a choice between hard-edge nationalism and the policies of “a leadership class that worships globalism.” He attacked Clinton for flip-flopping on her past support for the Trans-Pacific Partnership, a trade pact negotiated by the Obama administration, and challenged her to pledge that she would void the agreement in its entirety.