On the Sept. 2, 2015, edition of MSNBC's "Morning Joe," former Vice President Dick Cheney, a foe of the deal, and Secretary of State John Kerry, one of its chief architects, sat for back-to-back interviews.

Kerry rejected the claim that the agreement "sunsets," thus allowing Iran the relatively unfettered ability to proceed with building a nuclear weapon. A number of provisions of the agreement expire over time. Several provisions last for 10 years, including a limit of 5,060 operating centrifuges and curbs on research and development on advanced centrifuges. Other provisions last for 15 years, including a variety of caps on uranium enrichment, international inspector access in no more than 24 days, and prohibitions on new heavy-water reactors and reprocessing. Meanwhile, continuous surveillance of centrifuge production areas would last for 20 years, while continuous surveillance of uranium mines and mills would last for 25 years. Iran must comply with the Nuclear Non-Proliferation Treaty. This commits Iran to not pursuing nuclear weapons. So Kerry was right that the agreement as a whole does live on, and scrutiny of Iran's nuclear ambitions will continue indefinitely. But his statement glosses over the fact that a number of key elements of the agreement expire in 10, 15, 20 or 25 years. On balance, Politifact rated the claim Half True.

Cheney said that one of the agreement's fundamental flaws is it allows Iran to continue to enrich uranium. However, the Nuclear Nonproliferation Treaty, or NPT, was designed in part to allow countries to pursue the peaceful use of atomic energy while preventing them from turning their nuclear materials and technology into weapons." Cheney is incorrect in asserting that the NPT prohibits enrichment by non-nuclear weapon states," said Daryl Kimball, executive director of the Arms Control Association. "Article IV of the treaty does not 'allow it,' nor does it prohibit it.' "Ultimately, while it's debatable whether the treaty grants nations the right to enrich, if a non-nuclear nation wants to enrich uranium for peaceful purposes, the treaty doesn't stand in the way. Politifact rates the claim False.

Santorum garbles message on climate change

Republican presidential candidate Rick Santorum claimed: "There was a survey done of 1,800 scientists, and 57 percent said they don't buy off on the idea that CO2 is the knob that's turning the climate. There's hundreds of reasons the climate's changed." What he's referring to is a finding by the U.N. Intergovernmental Panel on Climate Change in its fifth report. The IPCC has said it is "extremely likely" (a 95 percent confidence level) that humans are causing climate change. The IPCC also said it is "very likely" (a 90 percent confidence level) that greenhouses gases are the driver.

Santorum's 57 percent figure doesn't hold up." You don't get anywhere near 57 percent when surveying the broad earth science community, and you get very close to full consensus when you ask the experts in climate science," said Peter Doran, a professor of earth science at Louisiana State University. National Science Board member James Powell surveyed scientific journals, finding that the consensus in the literature is about 99.9 percent. And multiple independent studies have "asked scientists directly" and found consensus levels of around 97 percent, said William Anderegg, who studies climate change at Princeton University. "Those studies were rigorously peer-reviewed and thus should be considered more credible than a blog post that misreads an institute report," he said. Essentially, Santorum garbles a blog's textbook misinterpretation of a survey. Politifact rates the claim False.

Chip Tuthill is a longtime Mancos resident. Website used: www.politifact.com.