The United States suggested Thursday it was open to a “new arrangement” with Iran for peacefully resolving disputes such as Tehran’s recent ballistic missile tests. Setting the stage for President Barack Obama’s summit with regional leaders in Saudi Arabia later this month, US Secretary of State John Kerry met with the foreign ministers of the six-nation Gulf Cooperation Council to advance a series of proposals aimed at easing Arabs’ concerns about last year’s Iran nuclear deal and the warming of ties between the US and Iran. These include providing new counterterrorism, conventional military, missile defense and cybersecurity capabilities. Washington has...