WASHINGTON - The latest salvo in President Obama's campaign to eliminate nuclear weapons was fired Wednesday, delivered not by the administration, but rather by the man who presided over the collapse of America's Cold War rival.

Mikhail S. Gorbachev, who was president of the Soviet Union when it fell apart in 1991, called on the United States to ratify an accord to ban all nuclear test blasts, saying it would strengthen U.S.-led efforts to halt the spread of nuclear weapons.

"We have seen that dialogue with even the most recalcitrant governments is possible," Gorbachev wrote in a New York Times op-ed column, apparently referring to North Korea and Iran. "Yet dialogue can work only if the United States abandons the hypocritical position of telling others what they must do while keeping its own options open."

Gorbachev, who won the Nobel Peace Prize in 1990, is a leading advocate of nuclear disarmament. His call for U.S. ratification of the 1996 Comprehensive Nuclear Test Ban Treaty foreshadows the next major battle over arms-control policy after Obama's victory on Dec. 22, when the Senate ratified a new U.S.-Russia nuclear-arms reduction treaty.

GOP senators who tried to kill Obama's New START pact are expected to mount a vigorous effort to block the test-ban treaty, bolstered by five new GOP members.

The treaty would effectively add underground nuclear tests to a 1963 ban imposed on blasts in the atmosphere, oceans, and space. It would be enforced by a U.N.-run global network of seismographs and other sensors. It has been ratified by 153 countries, but can't take effect until it is ratified by the United States and other nations with nuclear programs, including China, Iran, India, Pakistan, and North Korea. The United States maintains a voluntary moratorium on testing.

Obama pledged to "immediately and aggressively pursue U.S. ratification" of the treaty in an April 2009 speech unveiling his ambitious goal of eliminating nuclear weapons.

Senate approval requires a two-thirds vote, or 67 of the 100 members, meaning the test-ban treaty will require the support of 14 Republicans - one more than those who supported New START.

The leading Senate opponent is the No. 2 Republican, Jon Kyl of Arizona, who argues that the United States can't risk relinquishing its ability to test - a contention that the administration and numerous independent experts reject.

Kyl, who led the bid to kill New START, also halted the Senate's first attempt to ratify the test-ban treaty in 1999.

Senate Foreign Relations Committee Chairman John Kerry (D., Mass.) predicted after the New START vote that the test-ban treaty would have a difficult path to ratification. "A whole lot of educating has to go on," Kerry said.

Some administration officials are less pessimistic.

"There's always been a bloc of [Senate] opponents historically to nuclear arms reduction and control," Assistant Secretary of State Rose Gottemoeller, the top U.S. arms negotiator, said Dec. 23. "That's part of a healthy debate; it's part of a healthy process."