Electronic warfare will always be a game of countermeasures, counter-countermeasures, counter-counter-measures, etc, ad nauseam. Anyone who thinks their shiny new F-35 automatically guarantees them 20 years of invisibility to the enemy is fooling themselves. The bad guy will buy/develop/steal better radar technology. IR detection technology will improve. Some new game-changing technology will come about where jets are detected from 100 miles away by the smell of the landing gear wheel bearing grease. And on and on. If I were the Israelis, I'd buy the F-15SE now, and start buying F-35's another 10 years from now, when the bugs have hopefully worked out. I gotta think the US would be all for this course of action too. Gotta keep those folks down at the F-15 production line in St Louis working!