In 2013, he introduced legislation with Senator Charles E. Grassley, Republican of Iowa, that would have incentivized states through grants to submit mental health records to the database that is used to check gun buyers’ backgrounds, known as the National Instant Criminal Background Check System. It also would have increased the maximum sentences for people found guilty of straw purchases and gun trafficking.
But Mr. Cruz, Texas’ junior senator, has almost uniformly opposed other measures aimed at combating gun violence. During the Trump administration, when Texas’ senior senator, John Cornyn, a Republican, successfully pushed to pass legislation requiring federal agencies and states to do a better job of reporting criminal offenses to the national background check system, Mr. Cruz kept his distance from the effort.
Gun control became a central issue in Mr. Cruz’s re-election campaign in 2018, when the Texas Republican fended off a challenge from his Democratic opponent, Beto O’Rourke, who was a House member at the time.
In that race, Mr. Cruz focused attention on Mr. O’Rourke’s support for a ban on purchases of assault weapons, warning voters that the Democrat wanted to “take our guns.” By contrast, months after the 2012 shooting at an elementary school in Newtown, Conn., Mr. Cruz voted against a measure prohibiting the sale of assault weapons.
“Assault weapons ban fails,” he wrote on Twitter at the time. “#2ndAmendment prevails #Protect2A.”
In 2019, when Mr. Cruz was asked about expanding background checks for all firearms sales over the internet and at gun shows, he warned that such a move would have a dispiriting effect on Republican voters.
“If Republicans abandon the Second Amendment and demoralize millions of Americans who care deeply about Second Amendment rights, that could go a long way to electing a President Elizabeth Warren,” Mr. Cruz said, referring to the Democratic senator from Massachusetts, who was seeking the Democratic presidential nomination at the time.
Last year, after a mass shooting at a grocery store in Boulder, Colo., that killed 10 people, Mr. Cruz renewed his complaints that Democrats were seeking to politicize the issue.