Did law enforcement's suspicion that a firearm would be found just inside the threshold of the home justify their search?

QUESTION PRESENTED Police officers were patrolling a residential neighborhood when they saw Petitioner walking on the sidewalk. They saw that he had something in his front pocket and suspected it might be a gun. Petitioner reached the front porch of his home as officers parked their car to speak with him. Petitioner placed the object that had been in his pocket behind the front screen door, then walked toward the officers and greeted them. One officer walked past Petitioner, opened the front screen door, and found a firearm behind it. The officers then determined that Petitioner was a felon and arrested him. The government has always conceded that officers lacked a warrant or even probable cause to search Petitioner’s home. But they have argued, and the Seventh Circuit agreed, that “reasonable suspicion” alone justified the search of the home. The question presented is: Did law enforcement’s suspicion that a firearm would be found just inside the threshold of the home justify their search?