The United States will not waver from its course of maximum pressure against Iran, Vice President Mike Pence said Monday, as tensions rise and the U.S.-brokered nuclear deal between the Islamic Republic and world powers appears to be unraveling with the Trump administration’s pullout. Pence’s assertion to a pro-Israel Christian organization that the U.S. “will never allow Iran to obtain a nuclear weapon” came on the same day that Iran began enriching uranium to 4.5 percent , breaking the limit set in the 2015 agreement sealed under President Barack Obama.