Rush Limbaugh, the relentlessly provocative voice of conservative America who dominated talk radio for more than three decades with shooting-gallery attacks on liberals, Democrats, feminists, environmentalists and other moving targets, died on Wednesday. He was 70.

His wife, Kathryn, announced the death at the beginning of Mr. Limbaugh’s radio show.

“I know that I am most certainly not the Limbaugh that you tuned in to listen to today,” she said. “I, like you, very much wish Rush was behind this golden microphone right now.” She added, “It is with profound sadness I must share with you directly that our beloved Rush, my wonderful husband, passed away this morning due to complications from lung cancer.” She did not say where he died.