WASHINGTON  James Bopp Jr. likes to begin speeches by reading the First Amendment. He calls opponents, including President Obama, “socialists.” He runs a national law practice out of a small office in Terre Haute, Ind., because he prefers the city’s conservative culture.

And for most of the last 35 years, he has been a lonely Quixote tilting at the very idea of regulating political donations as an affront to free speech.

Not anymore. Mr. Bopp won his biggest victory last week when the Supreme Court ruled that corporations, unions and nonprofit groups have the right to spend as much as they want supporting or opposing the election of a candidate.

Mr. Bopp was not present in the courtroom. His client  not for the first time  replaced him with a less ideological and more experienced Washington lawyer when the case reached the justices.