WASHINGTON — Texas is one of the most heavily armed states in America, but the issue of gun control hasn’t historically been a top issue at the ballot box.

It could be this year, however, in the closely watched U.S. Senate race between Sen. Ted Cruz and El Paso Rep. Beto O’Rourke.

Even before the polls closed on Tuesday, the Republican incumbent zeroed in on his Democratic opponent’s record on gun issues and said O’Rourke wants to seize Texans’ weapons, a signal that he will put the gun control issue front and center through November.

“Congressman O’Rourke is a vocal proponent of gun control and restricting the Second Amendment rights of law-abiding citizens,” Cruz said in a call with reporters Tuesday night. “But those anti-gun views are not reflective of the values of Texans.”

And he didn't slow down after the polls closed. Moments after the two easily clinched their respective nominations, Cruz released an attack ad saying O'Rourke "wants to take our guns" to the tune of Alabama's "If You're Gonna Play in Texas (You Gotta Have a Fiddle in The Band)."

Polls have consistently shown that guns aren't a top priority for Republican or Democratic voters in Texas, although the state has the most registered guns in the country, according to a 2016 report from the federal agency that regulates firearms.

Jim Henson, director of the Texas Politics Project at the University of Texas, said that could change if mass shootings spur political pressure on school safety or gun control. But even in recent years, guns haven’t moved to the top of the agenda in either party.

"These stories generate a lot of short-term attention," Henson said, adding that Republicans say the biggest issue for the Lone Star State is immigration and border security, while Democrats say it's political corruption, education and health care. "It doesn't break through in the issues that are front and center in Texas for partisans."

That hasn’t stopped Cruz and O’Rourke from discussing their vastly different approaches to gun violence or touting their diametrically opposed National Rifle Association ratings: Cruz has an “A+” and O’Rourke has an “F.”

Each points to the other's NRA record with scorn. O'Rourke says contributions to Cruz — more than $300,000 from the NRA and other gun rights groups in 2016, according to the Center for Responsive Politics — are evidence he's a shill for the gun lobby. Cruz has mocked, with disbelief, O'Rourke's pride in an F-rating from the NRA.

Beto O’Rourke

Last NRA rating: F

Total NRA contributions: $0https://t.co/PGtWuzzZ2t — Beto O'Rourke (@BetoORourke) February 25, 2018

Last week, Cruz re-introduced legislation with Sen. Chuck Grassley, R-Iowa, that they say would fix the broken national background check system used for gun purchases. The pair introduced it in 2013 as an alternative to Democratic efforts to ban so-called assault weapons and high-capacity ammunition magazines after the Sandy Hook shooting, but the measure failed.

And O'Rourke hasn't been shy about discussing gun legislation on the campaign trail, although his views may not be as popular among voters in a red, gun-loving state. The Democrat is backing a renewed effort to pass an assault weapons ban, unlikely to even come to a vote in the Republican-controlled House and Senate.

"I've got to face my kids and my conscience and do the right thing when we have the opportunity to do the right thing," O'Rourke said when asked on CNN if his gun views could cost him the election.

Here’s where Cruz and O’Rourke stand on gun issues:

Background checks

Since the Sutherland Springs church shooting in November, O’Rourke has pushed for universal background checks, which would require a federal background check in almost all gun purchases.

Cruz is opposed to universal background checks and has even kept his distance from a bill by Texas Sen. John Cornyn that would penalize federal agencies that fail to report records and incentivize states to send criminal history records to the National Instant Criminal Background Check System.

Cruz said repeatedly that his failed 2013 background check amendment would have prevented the violence in the tiny Texas town by filling in the gaps of the FBI database. The Air Force admitted it did not send shooter Devin Kelley's court-martial and conviction for domestic violence to the database used to approve gun buyers.

"The Democrats filibustered the legislation that would have resulted in this shooter being in federal prison instead of murdering those innocents in that Texas church," Cruz said on Fox News one day after the shooting.

The amendment would have incentivized states to provide mental health records. However, it would have also lowered the cap on grant money intended to help states report the records from $100 million to $20 million. Federal agencies would also have to provide a report to Congress on how many records they submit to the database.

After the shooting at a high school in Parkland, Fla., Cruz said again that the amendment could have prevented a mass shooting by adding additional armed officers in Parkland. It would have provided $30 million per year to schools through the Secure Our Schools grant.

Meanwhile, O’Rourke has pushed for universal background checks, an issue opposed by the NRA and GOP lawmakers like Cruz. Universal background checks would close federal loopholes, like those at gun shows.

“In those states that have adopted [universal background checks], you have seen a 50 percent reduction in gun violence against an intimate partner,” he said in a February town hall. “That’s a great place to start, and I’ve listened to gun owners and non-gun owners, Republicans, Democrats and independents on this.”

There hasn't even been a discussion allowed in Congress on common-sense gun safety laws. Let's have a debate. We owe our country that much. pic.twitter.com/hlKckPDUBX — Beto O'Rourke (@BetoORourke) February 21, 2018

The Fix NICS bill and the Cruz-Grassley measure would not address the gun show loophole, or private sale loophole, which allows unlicensed dealers to sell guns without running a federal background check on the buyer. Cruz disputes that a gun show loophole exists.

O'Rourke is a co-sponsor on a bill to address gun show sales. New York Rep. Carolyn Maloney's "Gun Show Loophole Closing Act of 2017" would require background checks for all firearm sales at a gun shows. The bill has no Republican lawmakers as co-sponsors.

Bump stocks and magazines

Cruz has stayed away from weighing in on bump stocks, the devices used in the Las Vegas shooting that allow a semi-automatic rifle to fire at nearly automatic rates, while O’Rourke has signed on to a bill to ban the aftermarket accessories. A ban on bump stocks will likely to be implemented soon but not through a bill in Congress.

In a radio interview with Dallas radio station KSKY-AM (660) in October, Cruz urged Congress to first gather all the facts.

"Once we do that, then we can ask what public policy steps could have prevented" the violence, he said. Cruz has not signed on to any measures in the Senate that would ban the device.

He dodged the issue on Tuesday’s call with Texas reporters, declining to say whether he supports a ban.

O’Rourke, on the other hand, signed on to bipartisan legislation by Reps. Seth Moulton, a Massachusetts Democrat, and Carlos Curbelo, a Florida Republican, to ban the devices. The bill would have banned the manufacture, sale, and use of bump stocks and similar accessories.

"I think banning bump stocks makes a lot of sense," O'Rourke said in an interview with CBS News.

The measure appears to have stalled. GOP lawmakers pushed for ATF to handle the ban rather than Congress.

In December, the Justice Department and the Bureau of Alcohol, Tobacco, Firearms and Explosives announced that they would re-examine the legality of the device, despite a 2010 ATF review that determined the agency did not have the authority to regulate the devices because they do not fall into the category of a "machine gun."

Last month, President Donald Trump announced that he had directed the Justice Department to draft regulations to ban the devices. Bump stocks were not used in mass shootings in Sutherland Springs and the Florida high school.

Other gun accessories like high-powered magazines are often under scrutiny after mass shootings.

On Tuesday, Cruz sidestepped questions about whether he would support a ban on high-capacity ammunition magazines that allow shooters such as the Newtown killer to continue firing without having to pause to reload.

He noted only that automatic weapons have been banned for 70 years, that the ATF allowed the sale of the device during the Obama administration and that Trump has ordered a ban.

On the campaign trail earlier this month, O'Rourke told reporters in Longview that he's ready to debate gun measures, such as a bill to ban high-powered magazines. After Las Vegas, Democratic lawmakers renewed their efforts to pass such a ban.

Raising the age to purchase guns

Cruz opposes raising the age for long guns, which is currently 18 under federal law, while O’Rourke wants a complete ban on AR-15-style rifles, no matter the age.

A measure to raise the age has some support from Republican lawmakers like Arizona Sen. Jeff Flake, but Cruz told Business Insider that "legal adults have the right to defend themselves." Federal law requires a buyer be 21 if they are purchasing a handgun but not a long gun.

"The Bill of Rights applies to all adults, not just those Washington wants it to apply to," Cruz said. "I believe we should be protecting the Second Amendment rights of law abiding citizens.”

In multiple interviews since Sutherland Springs, Cruz invoked memories of surveying the bloody church before talking to residents, who brought up guns.

"When I was at the hospital with the victims, with the victims' families, over and over again what they said to me in Texas — they said gun control is not the answer here," Cruz said about a ban on AR-15s on Fox & Friends.

O’Rourke wants Congress to go further than raising the age.

"I don't know that we should raise the age for buying an AR-15. I just don't think we should be selling AR-15s in this country," O'Rourke said in an interview with CBS News. "That weapon was designed for one purpose and one purpose only — to kill people as effectively and efficiently as possible on the battlefield. It has no place in our streets, in our schools, in our concerts, in our movie theaters."

Concealed carry reciprocity

Cruz is a co-sponsor of the NRA-backed bill that would allow gun owners use a concealed carry permit from their home state anywhere in the country. O’Rourke voted against the House version of the bill in December.

Cruz's support of concealed carry reciprocity is one of the reasons Gun Owners of America endorsed him for president in 2015. The group called the issue one of their "chief priorities in Congress."

O'Rourke voted against the House version of the measure, saying it would make Americans "less safe" in a blog post after the vote. The House version was attached to Cornyn's "Fix NICS Act." It's unlikely that the combined bill would pass the Senate, and Cornyn has said it would be better to consider each measure separately in the Senate.

Texas does not allow those with convictions for stalking and domestic abuse to obtain a license to carry. O’Rourke argued that the bill would force Texas to allow states with less-strict rules in place.

“We should hold those from out-of-state to these same standards when they travel to our communities,” he wrote in December.

Arming teachers

Cruz has been vocal about his support for arming teachers, a position he’s taken since Trump suggested the idea after the Parkland shooting.

In a CPAC appearance, Cruz argued that teachers should be allowed to carry firearms into classrooms.

"It makes perfect sense that if teachers want to exercise their right to keep and bear arms, that only makes schools safer,” Cruz said. “I don't think you should make teachers do that, but if a teacher is comfortable and wants to be prepared to defend himself or herself, that's a good thing."

But O’Rourke says teachers want to focus on teaching, not carrying guns.

"Arming our teachers is not the answer to stopping the repeated occurrence of school shootings that disproportionately happen in our country, in our classrooms, to our kids," O'Rourke said in a statement, adding that Texas "should be leading the way" to push for gun control measures.

Washington correspondents Todd J. Gillman and Katie Leslie contributed to this report.