Sen. Ted Cruz is obnoxious. Sen. Marco Rubio is nice. That’s why so many Republican politicians, donors, and party leaders want the senator from Florida, not the senator from Texas, to be the Republican nominee for president. They think Rubio would attract more voters than Cruz in a general election, and polls suggest they’re right. But the polls and pols miss an important factor: Tactically, Cruz is smarter than Rubio. That difference is becoming clearer as the candidates grapple with the death of Supreme Court Justice Antonin Scalia.

In his three decades on the court, Scalia cast the deciding vote in dozens of cases. His departure raises the prospect that a new liberal justice could supply the fifth vote to overturn these rulings. A Republican presidential candidate who wants to scare and mobilize conservative voters could choose to highlight any of the issues at stake, from contraception to campaign finance to the death penalty. Over the weekend, Cruz and Rubio chose their issues. Rubio picked gay marriage. Cruz picked guns.

At the start of Saturday night’s debate in Greenville, South Carolina, the candidates were asked for their thoughts about Scalia. Rubio praised the late justice’s “dissent on Obergefell,” the 2015 case that struck down laws against same-sex marriage. In his closing statement, Rubio added, “We’re going to be a country that says that marriage is between one man and one woman.” On Fox News Sunday, he repeated that “marriage is between one man and one woman” and that “Obergefell should be overturned.”