Cass Sunstein defines it as the idea that “if the U.S. acts on its own, it will impose costs on the American people without seriously addressing the climate problem.” He then makes the case that it should guide policymaking rather than discouraging it:

No sensible person thinks that the U.S. should spend billions of dollars to achieve small greenhouse-gas reductions. Some imaginable initiatives should be rejected because they would cost too much and deliver too little. At the same time, the U.S. should not overlook opportunities to produce significant emissions reductions at justifiable expense. Recent regulations have easily passed that test. Future initiatives should be embraced when they do so as well.

Those who make the Sophisticated Objection are correct to emphasize that to limit the risks of climate change, many nations will be required to act. But unilateral action should not be avoided for that reason. On the contrary, pragmatic steps by the planet’s most important nation are likely to help spur action by others — and to lead to technological advances that will ultimately be in the interest of the world as a whole.

Reihan offers some qualified support:

He goes too far, in my view, by suggesting that recent regulations “have easily passed” the test of producing “significant emissions reductions at justifiable expense.” Yet I think that there is a nontrivial reason to believe that the health benefits of reducing carbon emissions, e.g., the impact on infant brain health, might be large enough to justify some kind of carbon price even if we disregard the climate change question entirely, as MIT economist Christopher Knittel has suggested.

This again was once a conservative idea: let’s innovate non-carbon energy anyway because it would obviously be a good thing under any circumstances. Instead they got their heads wrapped around hoaxes and ended up looking like know-nothing fanatics.