Former New York City Mayor Rudy Giuliani's campaign for the Republican nomination may be struggling but the Mars Society backed him as he prepared for a primary in a state known as a base for space exploration. The group urged other candidates to follow the lead of Giuliani and his rival Sen. John McCain (R-Ariz.) on Monday, on the eve of the Florida primary.

Giuliani authored an opinion piece in Florida Today, calling for an increase in NASA spending. He specifically said that the Commercial Orbital Space Transportation Systems Program should receive more funds because it aims to stimulate private investment in space exploration.

McCain issued a policy statement supporting for the return of human exploration of the Moon and eventual human exploration of Mars.

Hillary Clinton and Barack Obama have also announced positions supporting further need for space exploration and robotics.

"Both plans talk about improving NASA in the broader context of improving research and science education in America, but fail to specifically mention human exploration of the Moon or Mars -- leaving open the possibility that either administration could leave human spaceflight programs stalled in low-Earth orbit," the Mars Society said in a prepared statement.

Mars Society Political Director Chris Carberry said Giuliani and McCain each demonstrated a "can-do attitude" toward space exploration.

"Luckily, space exploration is an area where bold presidential leadership can make a difference," Carberry said in a prepared statement. "The Mars Society calls on all of the presidential candidates to release detailed plans for NASA that help ensure American leadership in human space exploration."