Addressing the United Nations General Assembly on Tuesday, President Trump attacked his favorite whipping horse — globalism — in its greatest stable.

Trump was explicit. "The future does not belong to globalists. The future belongs to patriots. The future belongs to sovereign and independent nations." Lamenting the failure of international organizations to deal with abusive practices such as China's trade policies, Trump continued, "For years, these abuses were tolerated, ignored or even encouraged. Globalism exerted a religious pull over past leaders, causing them to ignore their own national interests. But as far as America is concerned, those days are over."

There is a lot of truth in those words. Bound to the democratic rule of law, positive nationalism serves better lives and sources genuine cooperation in global relations. Trump is right to make the case for this ideology, especially since too many unfairly now present it as some kind of inherent evil.

Yet the problem for Trump is that his words will fall on silent ears.

Because when Trump, as he did on Tuesday, talks about the success of the U.S. economy, he sparks those listening in the assembly to raise their eyebrows and think, "This guy is only interested in his own ego." And to some degree they have a point. In an international forum, the focus should really be on international issues.

The broader point here is that Trump could achieve much more were he willing to woo these leaders with a little more focus on their concerns. That doesn't mean sacrificing America interests at the altar of globalist gimmicks such as the Paris climate accord. But it does mean he should express more cogently why that deal is bad for America — especially the poorest Americans, why it does little to reduce global carbon emissions, and what alternatives Trump would support.

Earning that better favor also means Trump avoiding the kind of juvenile insults that he lobbed at 16-year-old climate activist Greta Thunberg on Tuesday. Such antics do nothing positive beyond serving Trump's humor. They alienate world leaders into believing Trump is neither a serious statesman nor has interest in becoming one.

That's a great shame. Defending international democratic order against China, Trump has proven himself a 21st century Harry Truman. But why stop there? Trump should do more to win over those who want and need American leadership.