Israel is America's good friend, Democratic presidential candidate Pete Buttigieg said Monday. And that means providing some tough love when it's warranted.

Americans themselves can be patriotic while still not supporting the sitting president, the South Bend, Indiana mayor told thousands of people at the national conference of J Street, a liberal pro-Israel group. In that same vein, "you can be committed to the U.S.-Israel relationship without that (meaning) you are supportive of any policy choice by a right-wing government," Buttigieg added, drawing applause as he referred to the current governance of Israel.

The United States, Buttigieg said, should view international relationships with allies as a "friendship where your friend is acting in a way that might hurt your relationship, hurt them and hurt you. You put you arm around your friend and try to guide them to a better place," the mayor said.

Buttigieg on the Trail View All 16 Images

J Street, which defines itself as pro-Israel, pro-peace and in favor of a two-state solution to the Israeli-Palestinian conflict, is hearing from five of the Democratic presidential candidates at its Washington, D.C. conference.

Buttigieg affirmed what the crowd wanted to hear – an opposition to new settlements or annexation. The mayor said if he were president, he would ensure no U.S. taxpayer funds would be used to pay for such policies (though he did not suggest cutting off U.S. aid to its ally).

But he won some of his loudest applause when he lamented how the behavior and policies of President Donald Trump have eroded U.S moral authority and leadership in the world. Trump has been roundly criticized, most recently, for pulling troops out of northern Syria, abandoning Kurdish allies who have fought alongside American troops to counter ISIS.

Speaking about his time as a Navy officer in Afghanistan, Buttigieg said, "when I was deployed, I could feel… the power of the flag on my shoulder. Just as much as my body armor or any military equipment, part of what was keeping me safe was that our flag stood for a country known for keeping its word. Losing that is unbelievably costly anywhere in the world where we are counting on our allies to protect American troops and American interests," Buttigeig said.

Recalling Trump's September speech at the United Nations – which the mayor said he was grading "on a curve" – Buttigieg said he was saddened to see a visual display of the change in U.S. influence worldwide.