CHINA’S NEW PRESIDENT, Xi Jinping, appears to have concentrated his power with remarkable swiftness in recent months. “Xi has outmaneuvered his rivals, his colleagues, and even his mentors,” reports the European Council on Foreign Relations. But to what end? The early hopes that Mr. Xi would be a political reformer are vanishing. Instead, he seems determined to impose more Communist Party control on both state and society while still pursuing economic modernization. It’s a familiar recipe and profoundly misguided.

On July 16, police detained one of China’s most prominent human rights activists, Xu Zhiyong, who has been at the forefront of a movement to defend citizens’ rights based on the constitution and rule of law. Mr. Xu, a legal scholar, is among those who believe that the best way to battle the system is to demand that it follow its own rules — and not the whims of the party. He has also been outspoken against corruption and the widespread practice of Communist officials enriching themselves with bribes and accumulating hidden wealth. The New York Times reported that he was detained in reprisal for this campaign.

The strange thing is that Mr. Xu’s positions are not far from those articulated by his new president. In December, Mr. Xi gave a speech on China’s constitution. He declared, “We must firmly establish, throughout society, the authority of the constitution and the law and allow the overwhelming masses to fully believe in the law.” These words heartened some reformers who thought they might signal that Mr. Xi would put less emphasis on the party and more on the rule of law.

But it has not happened. The detention of Mr. Xu suggests that the powerful machinery of Chinese state security remains on the prowl against those who challenge the party’s monopoly on power. Recently, authorities issued a directive to universities, banning discussion of press freedom, judicial independence, universal values, citizens’ rights, civil society cronyism and the party’s historical mistakes. Thus, issues at the core of China’s political black hole — a system in which the party-state stands above human dignity, freedom and rule of law — are banned. They will be discussed quietly nonetheless, but the directive is a sign of rigidity from above.

Moreover, in recent weeks Mr. Xi has been promoting still more power and prominence for the party in the nation’s affairs. He has called on party members to toe a “mass line” against excess and extravagance, words that harken back to the revolutionary era of Mao. Mr. Xi seems to want to pursue economic modernization without giving an inch to its political equivalent. China’s leaders like this formula, but it has always carried risks, which now may deepen. The more people taste economic good times — as hundreds of millions are doing in China today — the more they may feel empowered and entitled to a political voice. It won’t happen all at once, but such aspirations can’t be easily extinguished by just slamming a fist on the table, arresting more dissidents and invoking the words of Mao.