While President Obama called for a “moral awakening” in Hiroshima and restated his ambition for a nuclear-weapon free future, back in Washington, Sen. Ed Markey, D-Mass., criticized him for moving forward with a costly plan to renovate the U.S. nuclear arsenal.

“The U.S. cannot preach nuclear temperance from a bar stool,” Markey wrote in a Boston Globe opinion piece.

Obama’s Hiroshima speech was reminiscent of the one he gave in Prague, only three months into his presidency, when he announced that he would “seek the peace and security of a world without nuclear weapons.”

In 2010, he negotiated a treaty that limited the U.S. and Russia to 1,550 deployed, strategic nuclear weapons each.

But that was as far as he would go. Obama is set to maintain the U.S. arsenal of 1,528 deployed warheads — almost half of which are on 30-minute alert — despite a 2013 White House assessment that he could safely reduce the U.S. arsenal by a third.

Obama is also pushing for a $1 trillion effort to replace the U.S.’s entire stock of long-range strike bombers, cruise missiles, nuclear submarines, and land-based missiles – which experts have said is sure to cause an arms race.

Markey attacked the modernization program on the Senate floor on Thursday. “The United States must take the lead,” Markey said, “instead of wasting billions of dollars on dangerous new nuclear weapons that do nothing to keep our nation safe.”

Markey also promoted a measure he introduced to delay the procurement of the new nuclear cruise missile, which he called a destabilizing and “dangerous new weapon.”

Erica Fein, nuclear policy expert with Women’s Action for New Directions, said it was courageous for Markey to “call out [his] party leader, something only a handful of other Democrats have been willing to do on this topic.”

Last month, Republicans on the House Armed Services Committee lined up to kill a measure that would require the Congressional Budget Office to simply estimate the modernization’s cost over three decades.

But last week, at an event at the Brookings Institution, Sen. John McCain, R-Ariz., broke ranks with his own party, calling the new generation of submarines “very, very, very expensive” and questioning, “Do we even need the entire Triad given this situation?”