If you pay the piper, you get to call the tune. The U.S. Supreme Court undercut that traditional conservative First Amendment principle today in Agency for International Development v. Alliance for Open Society International, striking down a law that required recipients of federal funding for AIDS prevention abroad to have a policy opposing prostitution. In a 6-2 decision, Chief Justice John Roberts wrote that though the government can decide what speech it wants to fund, it can’t condition funding on making you say something outside the scope of the program being funded.

Roberts’s vote -- and Samuel Alito’s alongside his -- show how sharply the ideological lines on free speech have changed. Stay up late at No. 1 First Street NE tonight: The ghost of Roberts’s predecessor, Chief Justice William Rehnquist, will be walking the ramparts, wondering how his former law clerk could have poured the poison in his ear.

The 2003 law in question reflects the George W. Bush-era version of international HIV/AIDS prevention. It restricted funding to only organizations that have a policy explicitly opposing prostitution -- a serious impediment for organizations that want, for example, to prevent the spread of the disease by working with prostitutes. The court said nothing about the wisdom of the policy, however. Instead it approached the questions from the standpoint of what the government can require from its grant recipients.

Political Struggles

That is where history comes in -- specifically the history of conservative versus liberal struggles on the Rehnquist court. In 1991, in the landmark case of Rust v. Sullivan, Rehnquist wrote an opinion for a 5-4 court upholding a law that banned clinics receiving federal family-planning funds from counseling or referring women for abortion. Rehnquist wrote that the requirement wasn’t abridging the clinics’ or the doctors’ free speech -- they could, he said, create other clinics, not supported by federal money, and counsel for abortion there. Free-speech advocates were outraged, but the logic reflected Rehnquist’s view -- going back to the 1970s -- that recipients of disability or welfare payments must “take the bitter with the sweet,” not claiming constitutional protection when the government took away funding it had provided out of its “largesse.”

An application of this view, adopted by Justice Antonin Scalia in dissent in the new AIDS prevention case, says that when the government sets conditions on receipt of funding that are relevant to the program, it isn’t coercion. No one is forced to take the money, and so no one is coerced either to speak or to remain silent. The organizations that don’t want to have policies formally opposing prostitution, Scalia said, can do whatever they like -- they just can’t use this federal money to do it.

A few years ago, you would have expected conservatives such as Roberts and Alito to have adopted this view. But the politics of federal funding are changing, and conservative doctrine is changing with it. Once, the government was imposing morally conservative conditions, like the anti-abortion counseling rule in Rust or the anti-legalized-prostitution condition in the 2003 law. Now, in the wake of the Affordable Care Act, the conditions imposed by government can be liberal -- like Obamacare’s so-called contraceptive mandate that requires big organizations to provide contraceptives as part of their health-insurance plans. Conservatives are growing concerned that government conditions might impinge on individual liberty. Roberts and Alito, younger than Scalia and Thomas (and less constrained by long voting records), are more affected by this shift.

Fine Line

Instead of the old conservative position, Roberts asserted that there is a fine, if fuzzy, line between the government limiting or requiring speech that defines the limits of a program, and setting “conditions that seek to leverage funding to regulate speech outside the contours of the program itself.” In Rust, he claimed, the condition of not mentioning abortion was on the project itself, not on the grantee. In contrast, Roberts maintained, the anti-HIV/AIDS law requires that the applying organization explicitly adopt a certain policy extending beyond the narrow goal of fighting HIV/AIDS.

Thus, although Roberts claimed to be relying on Rust, he was in fact limiting its scope. After all, the requirement that grantees set up separate facilities should they want to offer abortion-related counseling was in effect a requirement to create organizational separateness -- just what the anti-HIV/AIDS organizations would have had to do under the law that the Roberts court has now struck down.

This result is a good one if you like free speech, and fear that government funding can be used as a powerful tool to shape private speech (potentially thought, too). But make no mistake about the context: Roberts and Alito are gearing up for a world where exemptions and protections from generally applicable laws will be sought primarily by conservative groups. The main framework will probably be religious liberty, which opponents of same-sex marriage have increasingly identified as the value under attack when government recognizes same-sex marriage and requires various organizations to do the same. But free exercise of religion is in the First Amendment, too. If he could be made to understand the new emerging politics of the First Amendment, Rehnquist’s anguished ghost might be appeased.

(Noah Feldman, a law professor at Harvard University and the author of “Cool War: The Future of Global Competition,” is a Bloomberg View columnist. Follow him on Twitter at @NoahRFeldman.)

To contact the writer of this article: Noah Feldman at noah_feldman@harvard.edu.

To contact the editor responsible for this article: Mary Duenwald at mduenwald@bloomberg.net.