During the first presidential debate, President Trump hailed his efforts to restrict travelers from China as evidence of his administration’s effective response to the covid-19 pandemic, saying the “early” decision “saved thousands of lives.” He went on to claim that his opponent, Democratic nominee Joe Biden, would have opted to close the country late, resulting in 2 million deaths — a tenfold increase in lost American lives.

The president is incorrect. The United States did not implement its travel restriction early. Nor did it “close” the country to arrivals from China. In addition, there is little evidence that travel restrictions alone saved millions of lives — in this country or any other. On the contrary: Unless the United States and other nations act, the widespread use of travel bans in this pandemic have made Americans and citizens of other countries more vulnerable to future pandemic threats.

Forty-five nations imposed travel restrictions on China before the United States did. The earliest of those restrictions went into effect Jan. 24, nine days before the U.S. travel ban went into effect on Feb. 2. The U.S. travel restriction came a month after China first announced its outbreak and at a point when the United States and more than 20 other countries had already reported coronavirus cases. Several of those countries, including Germany and the United States, were already reporting local transmission of cases. Between the first official report of an outbreak in China and the announcement of U.S. travel restrictions, more than 40,000 travelers from China were estimated to have entered the United States. Scientists believe the virus likely emerged and began circulating a month or more before it was first recognized in China, which may have allowed it to spread beyond the countries where cases were initially recognized.

The measure that the Trump administration implemented could not be described as a “ban” that “closed the country”: It only prohibited U.S. entry to foreign nationals who had visited China in the last 14 days. Americans and U.S. permanent residents returning from Hubei Province were still allowed, subject to a 14-day quarantine. After these policies were enacted, hundreds of thousands of travelers continued to arrive in the United States via direct flights from China. Until Feb. 27, no other travelers to the United States faced such travel restrictions and quarantine requirements — even if they were arriving from other nations that were reporting coronavirus cases.

Restricting flights from China did nothing to prevent the virus from arriving from other parts of the world. Genetic analyses have shown that the large epidemic that unfolded in New York was linked to travelers from Europe. In the early days of the U.S. epidemic, testing was restricted to people with a travel history to China, which limited the ability to detect locally the cases and infections among travelers from other countries.

By the time Trump expanded travel restrictions to Iran on Feb. 28 and to European nations on March 12, it was largely too late. By mid-March, the United States was approaching 2,000 confirmed cases and experiencing severe shortages in testing capacity that meant many infections likely went undiagnosed. The travel restriction did not initially apply to the United Kingdom, which already had hundreds of reported cases. And, implementation caused chaos. Photos showing large crowds of Americans stranded together in long lines and tight corridors for hours at airports may have increased virus transmission among those travelers who eventually made their way back to the United States.

The best evidence for travel bans are in nations that used them as part of a comprehensive strategy against the virus. The combination of travel restrictions within China and international travel restrictions against China may have delayed the spread of the coronavirus across the globe in the first 50 days of this pandemic. Those delays were useful to nations such as New Zealand, Australia and Taiwan that used the opportunity to expand testing, contact tracing and other aggressive domestic measures to control the spread of the virus. The United States did not do so. Before March 1, U.S. public health departments conducted fewer than 100 tests.

The United States is not the only country where travel bans against China proved ineffective in stopping or slowing the spread of this virus. Some of the countries with the most reported coronavirus cases, such as India, Iran and Italy, also implemented travel restrictions against China on the same day or earlier than the United States. Before this pandemic, the World Health Organization had warned that travel bans contribute to “a false impression of control” — the misperception that a ban would stop the spread of disease. The reliance on travel bans over domestic readiness, in the United States and elsewhere, suggests the WHO had a point.

By March 25, the number of nations that had imposed travel restrictions in this pandemic had increased to 136. A few nations used well-designed travel restrictions effectively as part of a comprehensive response to the pandemic. Others, such as the United States, deployed increasingly broad travel restrictions, designed more with politics than public health in mind. While it’s prudent to avoid traveling as a means of limiting exposure to the virus, the more than 34 million cases reported so far by 188 countries make it hard to argue that travel restrictions have helped stop the pandemic from spreading across the globe.

The widespread use of travel bans leaves a legacy that extends beyond the current crisis and can make us less safe against future pandemic threats as well. Historically, governments often delayed reporting dangerous disease outbreaks to the WHO and other nations out of concern that other governments would impose tough trade and travel restrictions against them, which could have severe economic consequences. In 2005, the international health rules were revised to keep countries from closing borders or restricting trade in an outbreak, unless those restrictions were science-based and no more restrictive than needed. The extensive adoption of travel restrictions in this pandemic, over WHO guidance to the contrary, will only reinforce nations’ original impulses to keep outbreaks hidden.

The world is at a crossroads: We can adopt stricter international health rules on the use of such bans or create a new system of global surveillance of pandemic threats that is much less dependent on the self-reporting of early affected states. Either approach will require global leadership, marshaling the support of allies and rivals alike, and working with the WHO. It is a worthy agenda for the next president — and a far better subject for the next debate than what Americans heard Tuesday night.

Read more: