Sen. Bob Bennett, R-Utah, is on board, but Sen. Orrin Hatch is not yet sold on New START, which would reduce long-range nuclear weapons from 2,200 to 1,550 in the next decade and restart on-site inspections between the nations.
Hatch said he's worried the reduction in warheads may leave the nation vulnerable and he's concerned the treaty would block the United States from developing missile defense systems.
"What happens if we reduce our nuclear arsenal that has served as an effective deterrent too much?" Hatch asked. "While I am reviewing this treaty, I do have concerns that need to be addressed."
President Barack Obama is pressing the Senate to ratify the treaty before this session ends in the first days of January and the Democratic majority shrinks from 58 seats to 52. It takes a two-thirds vote to approve a treaty, so whether the Senate votes soon or some time next year, Obama must have the support of at least some Republicans.
Bennett is ready to be one of those Republican votes, saying he thinks the treaty would help thaw relations between Russia and the United States, but he's not convinced the treaty will even come up for a vote before he leaves office.
With just a few weeks left in the year, lobbying efforts on both sides have intensified.
An arm of the conservative Heritage Foundation sent mailers to key states, including Utah, asking people to urge their senators to oppose the treaty, arguing it is a better deal for Russia than the United States.
On Sunday, The Salt Lake Tribune published an Op-Ed by Wilcox and Utah Attorney Mark Shurtleff backing New START and pointing out that it has the unanimous support of the Joint Chiefs of Staff and the Defense secretary.
Wilcox and Seelig participated in a broader lobbying day Monday in Washington, with their flights paid for by the Healthy Environment Alliance of Utah and Women's Action for New Directions. They met with Hatch and Bennett, but also Rep. Jason Chaffetz and the staff of Sen.-elect Mike Lee.
The bipartisan pair co-sponsored a resolution in the Utah Legislature in support of a Comprehensive Test Ban Treaty, largely seen as the next step after START. Their resolution received unanimous support.
"Our state has had to eat the impact of the Cold War through nuclear detonation testing," said Seelig, referring to Utahns harmed by the fallout from nuclear tests in Nevada.
For Wilcox, the primary issue is inspections. Since the original START Treaty lapsed a year ago, U.S. inspectors have not been able to keep an eye on Russian warheads and Russian inspectors haven't been able to see the U.S. stockpile.
"We have to be able to monitor those weapons," he said. "We have been blind for almost a year."