In the five states where Republican senators are retiring, the midterm elections could usher in a wave of hardliners who are nothing like their GOP predecessors.If Senate Republicans seem conservative now, just wait until next year. The 2022 midterms could usher in a wave of full-spectrum MAGA supporters who would turn the GOP conference an even deeper shade of red — and make the Senate a lot more like the fractious House. In the five states where Republican senators are retiring, the primary election fields to succeed them are crowded with Donald Trump supporters who have made loyalty to the...