David Koch, the billionaire libertarian who gave more than $1 billion to charitable causes but was better known for using his money to reshape U.S. politics, died Friday. He was 79 years old…

Though he was a liberal on social issues like abortion and same-sex marriage, Mr. Koch used his fortune to support conservative causes that favor lowering taxes, free trade and fewer regulations. He was the Libertarian Party’s 1980 vice-presidential candidate…

Their support of conservative causes became a lightning rod for Democrats, raising the ire of then-Sen. Harry Reid of Nevada, who in 2014 called Mr. Koch and his brother “un-American” and accused them of “trying to buy America” through campaign cash.

The network the brothers built includes more than 700 donors who give $100,000 or more a year, as well as a group called Americans for Prosperity that has chapters in 36 states. In terms of its influence on the conservative agenda in the U.S., the network is rivaled only by the Republican Party.