Sen. John McCain (R-Ariz.) delivered a sobering and bold plea to international leaders on Friday, urging them not to give up on America despite the divisive rhetoric of President Donald Trump.

McCain, one of many U.S. officials speaking at the 2017 Munich Security Conference, which brings together senior decision-makers from around the world to discuss security challenges, noted that a panel at the event asks the question of whether the Western world will survive.

In recent years, this question would invite accusations of hyperbole and alarmism. Not this year, he said in his prepared remarks. If ever there were a time to treat this question with a deadly seriousness, it is now.

McCain, one of the toughest critics of Trumps unclear ties to Russia, never actually named the president as he warned about threats to the Western world.

But it was clear who he was talking about as he imagined how Cold War-era diplomats would respond to the types of policies and messages being pushed by the Trump administration, like, say, a ban on Muslims and refugees , or constant attacks on the media , or a steady refusal to accept facts .

They would be alarmed by an increasing turn away from universal values and toward old ties of blood, and race, and sectarianism. They would be alarmed by the hardening resentment we see toward immigrants, and refugees, and minority groups, especially Muslims, McCain said. They would be alarmed by the growing inability, and even unwillingness, to separate truth from lies. They would be alarmed that more and more of our fellow citizens seem to be flirting with authoritarianism and romanticizing it as our moral equivalent.

He also dinged the Trump administration for being in disarray at a Q&A session later in the day.

Still, the Arizona senator said in his speech he worries most about people giving up on Western nations, and about the perception that the United States is laying down the mantle of global leadership. Western countries still have the power to maintain world order, but they have to have the will to do it, he said, offering reasons for why that power has been slipping.

We grew complacent. We made mistakes. At times we tried to do too much, and at others we failed to do enough, he said. We lost touch with many of our people. We have been too slow to recognize and respond to their hardships.

McCain ended his remarks on a defiant note, saying not to count America out even if the temptation to despair is greatest right now.

We must be vigilant. We must persevere. And through it all, we must never, never cease to believe in the moral superiority of our own values that we stand for truth against falsehood, freedom against tyranny, right against injustice, hope against despair, he said. I am a proud, unapologetic believer in the West, and I believe we must always, always stand up for it for if we do not, who will?

You can read McCains full remarks here .