Ultimately, Mr. Miller picked Senator Zirkin. There are plenty of valid reasons for him to do so. Although JPR, as it is known, has handled some thorny and high-profile bills in recent years that involve big questions about the constitution and the role of government in society, including gun control, the death penalty and marriage equality, the day-to-day business of the committee falls more squarely into Mr. Zirkin's zones of professional expertise — family law, criminal law, civil practice and so on. Mr. Raskin is a leader in the Senate's progressive caucus, but Mr. Zirkin's views and experience more closely align with those of Senator Miller, who is also a practicing attorney and relatively conservative. (Mr. Frosh, though a leading progressive voice, was also a practicing trial attorney.) The choice of Mr. Zirkin may also be part of a strategic retrenchment of the Senate now that the state will have a Republican governor after eight years of progressive politics under Gov. Martin O'Malley.