Isakson was appointed last week, along with Sen. Patrick LeahyPatrick Joseph LeahyDem senator mocks Pruitt over alleged security threats: 'Nobody even knows who you are' Pruitt tells senators: ‘I share your concerns about some of these decisions’ Protesters hold up 'fire him' signs behind Pruitt during hearing MORE (D-Vt.), to serve as one of two congressional delegates to the world body for the next 12 months. The position is largely ceremonial, but does give lawmakers a chance to attend sessions and meet with U.N. leaders, including possibly Secretary General Ban Ki-moon, if the opportunity arises.

“I'll make time to do it if he wants to, I can guarantee you that,” Isakson said.

The arms trade treaty is supported by human-rights activists and some religious leaders, who argue it would merely require the rest of the world to follow U.S. standards for arms exports. Gun rights advocates, however, worry it would open the door to regulation of civilian weapons in the United States.

The treaty has struck a roadblock at the U.N. after the Obama administration and other nations objected to a draft earlier this summer. It's now on the back burner as the world body is consumed with the crisis in Syria and the threat of war between Israel and Iran. Even if the measure cleared the U.N., 51 U.S. senators — including Isakson — have warned they won't ratify it.

Isakson said he'd also like to warn U.N. leaders about the kinds of actions that undermine popular support for the world body. He singled out hosting Iranian leader and Holocaust denier Mahmoud Ahmadinejad on Yom Kippur, the holiest Jewish holiday, and giving seats on the Human Rights Commission to known human-rights abusers.

“Those are the types of things that really tarnish the U.N.'s image with me,” Isakson said, not to mention “the average rank-and-file citizen.” 

“But quite frankly, disengagement from the world community and isolation has always served to get us into more trouble than to be engaged and involved,” he said. “You ought to dialogue first before you start throwing spears. And I think the UN provides an opportunity for dialogue.”