President Obama is taking a risk in visiting Cuba. He’s right that engagement can create opportunities for change on the island that the old policy of embargo and isolation did not. But unless Obama advocates strongly for political freedoms and human rights, his trip may be remembered as little more than bonding over baseball.

The president is expected to meet both with President Raúl Castro and with critics of his government, address Cubans live on state television and attend a baseball game between the Cuban national team and the Tampa Bay Rays — presumably with President Castro. It will not be easy, especially given the casual setting of a ballpark, to strike the right balance between proclaiming a new era of engagement between the long-hostile nations and applying meaningful pressure to Castro to effect long-overdue reforms.

The human-rights situation in Cuba hasn’t changed much since December 2014, when Obama and Castro announced an agreement to normalize diplomatic relations. As part of that agreement, Cuba made a commitment to release 53 political prisoners and to allow fact-finding visits to the island by the International Committee of the Red Cross and United Nations human rights monitors. Cuba freed the political prisoners, but the monitoring visits have not happened.

Although Cuba has held fewer long-term political prisoners in recent years, laws that allow the government to lock people up for speaking their minds remain on the books. The government increasingly relies on detention without charges to keep people from participating in peaceful marches and meetings. The Cuban Commission for Human Rights and National Reconciliation, an independent human-rights group, reported more than 8,000 such cases of arbitrary detention in 2015. Just during Pope Francis’s five-day visit in September, police detained more than 100 dissidents.

The government still controls most media in Cuba. A small, growing number of independent journalists and bloggers are active online, but the government sometimes blocks access to websites and subjects critics to smear campaigns and arbitrary arrests.

Cuba has made important progress in a few areas, including increased freedom to travel and broader internet access, but its repressive system remains firmly in place. Obama needs to use his visit to press President Castro to begin dismantling that system by unlocking websites, ending arbitrary detentions, and fulfilling the government’s commitment to allow visits by international human rights monitors.

President Obama’s policy of engagement denies the Cuban government one of its main pretexts for repressive rule. From now on, it will be harder for Castro to paint the victims of his government’s repression as agents of U.S. aggression. And that will make it easier for other countries in the region to stand up for human rights in Cuba.

To be most effective, pressure on Havana to change should come not from the United States alone, but rather as part of a multilateral effort. Governments in the region that may have been reluctant to criticize Cuba when the island faced a hostile neighbor to the north no longer have to choose sides. After leaving Havana, President Obama will travel to Argentina, where he will meet with President Mauricio Macri, whose 3-month-old administration has been vocal on human rights in the region. In the new era of U.S. engagement, Obama has a chance to convince Macri and others to weigh in.

Through his engagement policy, Obama has created an unprecedented opportunity to support the efforts of Cubans seeking to exercise their basic rights. He should seize it — in Havana by urging real reforms, and in Buenos Aires by starting to rally international pressure on Castro to deliver. Only then should he allow himself a seventh-inning stretch.

JOSÉ MIGUEL VIVANCO IS THE AMERICAS DIRECTOR AT HUMAN RIGHTS WATCH.