This week, President Barack Obama will make a historic visit to Hiroshima: the first place on earth where human beings were subject to the devastation of a nuclear weapon, dropped by the United States. He will be the first sitting U.S. president to make the trip.

It’s worth celebrating this bit of real progress: that a sitting U.S. president will for the first time stand in contemplation at Hiroshima Peace Memorial Park.

This is the president who in 2009 stood before a crowd in Prague to declare his commitment to seek “a world without nuclear weapons.” It is also the president who in 2009, on accepting a Nobel Peace Prize, declared that “compared to some of the giants of history who’ve received this prize…my accomplishments are slight.”

And it is the president who, months away from exiting the White House, is thinking about his legacy: how will he leave the world better than it was in 2008?

For us, it’s a time to remind this president of his best intentions and hopes, and of our willingness to stand with him to leave the world a better place. We must ask President Obama to lead the way toward a nuclear-free future and to abandon plans to spend $1 trillion upgrading the U.S. nuclear arsenal.

And while we're at it, let's remember how many more constructive ways there are to use that $1 trillion: from universal preschool to shoring up our safety net, there are probably one trillion better ways those dollars could be used than investing in dangerous and outdated weapons that no one wants.

We know where his best intentions are. Now he needs to know we’re with him.

Ask President Obama to lead the way to a nuclear-free world.

A version of this post first appeared at www.nationalpriorities.org