Mike Lee is against ratification of the Comprehensive Test Ban Treaty. In May, he was for it. But before that, he was against it.

Clearly, Lee is having difficulty deciding on this issue. That’s fine. It’s complex. But we would urge him to return to the position he held before he changed his mind the last time. In other words, we would urge him, if elected, to support ratification. Lee is the Republican candidate for the U.S. Senate seat from Utah now held by Bob Bennett. We also urge Sen. Orrin Hatch to support ratification.

Lee’s deputy campaign manager told The Tribune that the candidate bases his latest position against ratification on language in the treaty that bans “weapon detonation.” Under Lee’s reading, that would prohibit the use of a nuclear weapon in war.

An analysis of the treaty submitted to the Senate disagrees with Lee’s reading. It says that the language does not prohibit the use of nuclear weapons in war. That interpretation squares with common sense. This is not, after all, a treaty to prohibit the use of nuclear weapons in war. It is a treaty to prohibit test detonations of nuclear weapons.

Still, the two ideas are related. Most commentary on nuclear weapons takes it as given that any state that is attempting to build nuclear weapons will want to conduct test explosions to make sure that its designs work. One rationale for a test ban is to prevent the proliferation of such weapons to more nations.

The United States has conducted hundreds of nuclear test explosions, and most experts agree that no further testing is necessary to maintain the reliability of the existing arsenal. One reason why the United States should favor the treaty is because it would lock in the lead in nuclear weapons knowledge that the United States now has. Without testing, other nations would have a hard time catching up.

In fact, if the United States were to resume testing, to prove the reliability of new designs, for example, other nations would be free to test. That would allow them eventually to close the gap on the United States. So it really makes little sense for the United States to insist on further testing. However, if the United States did, at some future time, decide that new testing was so critical to national security that it outweighed other considerations, the United States could withdraw from the treaty.

We do not believe that Lee’s reason for not supporting ratification amounts to a serious objection. Particularly given Utahns’ sorry history of downwind exposure to fallout from nuclear testing, Lee should support ratification.