Most of the current lawmakers spending big on Facebook advertisements are Democrats running for president. That’s no surprise, given the effectiveness the social media giant gives them in reaching the slice of the electorate they need to raise money and qualify for primary debates.

Still, it’s notable that the one using the platform the most is Sen. Elizabeth Warren, the Massachusetts Democrat who has called for breaking up the tech giant.

In March, Warren said that, as president, she’d pursue a new theory of antitrust to go after firms like Facebook that, in her view, are using their market dominance to squelch competition. She said she’d force Facebook to relinquish two of its prize acquisitions: the photo-sharing site Instagram and the messaging service WhatsApp.

Some of the ads Warren has purchased on Facebook have touted her plan. Facebook removed those in March, citing its policy barring use of its corporate logo, but later restored them.