Sen. Chuck Grassley is encouraged by President Donald Trump’s meeting with North Korean leader Kim Jong Un, but said it’s too soon to declare success.“I would be very cautious,” Grassley told reporters Wednesday, adding later that despite the historic nature of the summit, it’s also premature to talk about a Nobel Peace Prize for the president.“They’re going to make the same mistake they did with Obama,” the Iowa Republican said about reports that two Norwegian lawmakers already had nominated Trump for the honor.President Barack Obama was awarded the Nobel Peace Prize in 2009.