Sen. Elizabeth Warren (D-MA) said today that, if elected president in 2020, her administration will break up the giants of the tech industry, including Amazon, Facebook, and Google.

The proposal is the most stringent stance taken by a candidate in the presidential campaign so far. Warren, pointing to the antitrust battle over Microsoft in the 1990s, said the companies must be broken up to stimulate competition in a monopolistic market.

“As these companies have grown larger and more powerful, they have used their resources and control over the way we use the Internet to squash small businesses and innovation, and substitute their own financial interests for the broader interests of the American people,” Warren said in a statement. “To restore the balance of power in our democracy, to promote competition, and to ensure that the next generation of technology innovation is as vibrant as the last, it’s time to break up our biggest tech companies.”

The proposal notes that major companies have tightened their grip on the digital market through mergers, but regulators have largely let those deals pass. The result, Warren writes, has been “a dramatic reduction in competition and innovation in the tech sector.”