CHINA DEVOTES enormous sums toward blocking information from reaching its people. Thousands of government workers and the equivalent of billions of dollars are required to maintain the world’s largest cordon on the Internet, censor the news media and black out information that the ruling elite considers threatening to its monopoly on power.

The campaign is now tightening the screws on both U.S. correspondents working in China and the news organizations that sometimes carry their reports back into that country.

Bloomberg and the New York Times have published penetrating investigations into the accumulation of personal wealth by high-ranking officials and their relatives. Both the Times’ and Bloomberg’s Web sites aimed at Chinese readers have been blocked within China, presumably as a result. Since November, Web sites of the Wall Street Journal and Reuters also have been blocked. Moreover, China is refusing timely renewal of visas for journalists from these organizations. Some correspondents have been told privately that the visa delays are specifically in response to their journalism. The goal is to discourage correspondents from filing honest reports.

China’s rulers fear that the free flow of information would undermine their grip. It would showcase vibrant democracies, where people choose their leaders, and reveal unpleasant truths about China. To some extent, they’ve been successful at keeping people in the dark. But the world today is a colossal communications network, and much of it does not stop at passport control. There are leaks and should be more.

Congress ought to urge the U.S. Broadcasting Board of Governors to allocate more funds for technology to help Chinese people circumvent the massive firewall, as a coalition of human rights and religious freedom groups recently suggested.

Passport control remains pretty effective when it comes to people, however, and China is also using this as a weapon. The Times and Bloomberg have nearly two dozen journalists whose visas are up for renewal by the end of the month, and they may be forced to leave if the visas are not granted. Vice President Biden was right to protest this crude tactic at the highest levels during his meetings in Beijing last week. In response, China’s foreign ministry said correspondents had been provided a “very convenient environment.” This was insulting, as if a soft couch was at issue, rather than strong-arming by the Chinese state.

Chinese journalists get an open door to the United States. This reflects U.S. values and is fundamentally correct. But perhaps, if China continues to exclude and threaten American journalists, the United States should inject a little more symmetry into its visa policy.