The talk radio host Rush Limbaugh died last week. He was 70.

His rise to prominence was the realization of a decades-old conservative dream, ushered in by Reagan administration deregulation that did away with requirements for balance on radio and television.

Mr. Limbaugh turned politics into edgy, meanspirited entertainment, tapping into a latent demand for pure conservative talk. His audience was huge, as was his influence on the Republicans. His approach — demonizing opponents, rejecting compromise, embracing conspiracy theories — shaped the party of former President Donald Trump.

Today, we look back on Rush Limbaugh’s career and how he came to have such outsize influence.