"We may have different political allegiances and world views, yet we share a common concern -- Iran's drive to be a nuclear state," Richard Holbrook, former U.S. ambassador to the United Nations; R. James Woolsey, former CIA director; Dennis Ross, special Middle East coordinator for former President Bill Clinton; and Mark Wallace, U.S. representative to the United Nations for management and reform, wrote in an opinion column published Monday in The Wall Street Journal.
"We believe that Iran's desire for nuclear weapons is one of the most urgent issues facing America today, because even the most conservative estimates tell us that they could have nuclear weapons soon," the quartet said.
Iranian President Mahmoud Ahmadinejad is to speak before the United Nations in New York this week.
U.S. leaders of all political stripes must set aside their differences and "send a clear and united message that a nuclear armed Iran is unacceptable," the four wrote.
Holbrooke, Woolsey, Ross and Wallace said they and others formed the non-partisan group United Against Nuclear Iran.
"(We) hope to lay the groundwork for effective U.S. policies in coordination with our allies, the U.N. and others by a strong showing of unified support from the American people to alter the Iranian regime's current course," they wrote.
2014: The Year in Music [PHOTOS]