Ah yes. They called it Progressivism and it involved massive government interference in the marketplace. Trust Busting. Income Tax. Good stuff I'm sure. Our present day Progressives are pushing for more of it. Lots more. Too much financial self-indulgence by the productive class, don't ya know.
If you study what existed right before that, there was massive governmental interference in the marketplace by monied interests. TR just turned that against them.
Modern government has become constant battle between such opposing forces - witness the massive government bailouts that went to corporate interests over the last year or so.