President Bill Clinton signs the Comprehensive Nuclear Test Ban Treaty at the United Nations in New York on September 24, 1996. (Jeff Christensen/courtesy Reuters)

Fifteen years ago today, President Bill Clinton signed the Comprehensive Nuclear Test Ban Treaty (CTBT). The treaty bars signatory countries from exploding nuclear devices. In signing the treaty with the same pen that John F. Kennedy used three decades earlier to sign the Limited Test Ban Treaty, Clinton called CTBT “the longest-sought, hardest-fought prize in arms control history.”

Clinton didn’t realize at the time how accurate and prophetic his statement was. CTBT faced substantial Republican opposition from the start. When CTBT finally came to a vote in 1999, it fell well short of the two-thirds vote needed for passage. CTBT thus became one of just twenty-one treaties to be defeated on the floor on the Senate.

As of September 2011, 182 countries have signed CTBT and 155 have ratified it. The treaty does not go into effect until all forty-four “Annex II states”—so-called because they are listed in Annex II to the treaty—sign and ratify the treaty. India, North Korea, and Pakistan have not signed the treaty. China, Egypt, Indonesia, Iran, and Israel have followed the U.S. lead and signed the treaty but not ratified it.

President Obama vowed in his April 2009 Prague speech that:

My administration will immediately and aggressively pursue U.S. ratification of the Comprehensive Test Ban Treaty. After more than five decades of talks, it is time for the testing of nuclear weapons to finally be banned.

Not quite. The political forces weren’t aligned in 2009 for rapid Senate action. They were even less aligned after the November 2010 elections and the successful but draining effort to persuade the Senate to approve the New START Treaty.

The scuttlebutt is that Obama hopes to move forward with CTBT after he wins re-election. The State Department has a fact sheet posted on how CTBT would make America more secure, and Under Secretary of State for Arms Control and International Security Ellen Tauscher gave a speech in California in July touting CTBT.

But of course if Obama is to push for CTBT’s approval in his second term, he first has to win re-election. And that, it is safe to say, is far from a done deal.

What are the best things you have read on the pros and cons of CTBT?