The Republican-led Senate unanimously approved a measure emphasizing the importance of NATO’s mutual defense pact, a not-so-subtle dig at President Donald Trump.

Sen. Lindsey Graham’s resolution passed 100-0 after Trump waffled on his commitment to Article 5. That’s the alliance’s “one for all, all for one” defense agreement.

During a visit to NATO headquarters on his first foreign trip last month, Trump did not explicitly affirm his support for Article 5. But last week, amid questions about how he viewed one of NATO’s founding principles, Trump did back the collective defense pact.

Graham, a South Carolina Republican who ran against Trump for the Republican presidential nomination, says the unanimous vote “should reassure our allies and give notice to our enemies that America stands firmly in support of NATO and our Article 5 commitment.”