How much room is left in the Grand Old Party for those who don’t tow the MAGA line, 100% of the time? On the day after the birthday of Abraham Lincoln, the nation’s first Republican president, Wisconsin Republican Mike Gallagher’s surprise Feb. 10 announcement that he would retire from the House of Representatives when his term ends has set us wondering. Gallagher is 39 years old and in just his fourth term in the House. He was viewed as a rising star in the Republican Party and in Wisconsin, where he represents Green Bay and areas around it. His voting record is solidly conservative. But he w…