Calls to break up big US tech firms are growing stronger. The impact could change global power structures.

Back in March when Elizabeth Warren, the Massachusetts senator and presidential hopeful, promised to break up Big Tech if elected to the White House, the idea seemed fringe and fanciful. In July, however, things got real – the US Department of Justice opened a wide-ranging antitrust review of Amazon, Apple, Facebook, and Google, following similar moves by the Federal Trade Commission (FTC) and Congress.