President Biden faces growing pressure to distribute coronavirusvaccines to other countries in response to aggressive “vaccine diplomacy” campaigns by China and Russia, a step he has until now ruled out while millions of Americans are still urgently seeking immunizations.

China’s efforts in particular will be a focus of a meeting Friday between Biden and the leaders of Australia, India and Japan. Aides say the four leaders may discuss an agreement in principle to pass out vaccine surpluses after their home populations’ needs have essentially been met.

The United States’ authoritarian adversaries — who worry far less about domestic opinion — have the field mostly free for the moment to send vaccines to nations from Mexico to Lebanon to Uzbekistan.

That has sparked a debate within the administration about how to balance national security, humanitarian needs and political concerns. Activists and experts warn that the United States could be missing a unique opportunity to regain worldwide influence after the isolationism of the Trump years….

…the reaction among Americans could be explosive if Biden supplies vaccines to other countries while many in the United States are still struggling to get the shots. Biden signaled this week that he feels pressure to balance domestic and global needs.

“If we have a surplus, we’re going to share it with the rest of the world,” he said Wednesday, when pressed on the issue. “We’re going to start off making sure Americans are taken care of first, but we’re then going to try to help the rest of the world.”

His remark followed an announcement that the United States has secured 100 million more doses of the single-dose vaccine developed by Johnson & Johnson, bringing the projected U.S. supply far past the number of Americans in line to receive shots this year.

Demand still outpaces supply in most of the country, but that is beginning to change.