Presidential hopefuls spoke about law enforcement, terrorism and gun control following the shooting in San Bernardino, Calif. (Sarah Parnass/The Washington Post)

Two mass shootings less than a week apart have quickly highlighted how guns, national security, abortion and the threat of terrorism are deepening the nation’s political fault lines ahead of next year’s election.

In essence, the events provided each side of the partisan divide with mirror-image, poster-child suspects who reflect their views of the biggest threats to Americans’ safety: a gun-wielding, white abortion opponent in Colorado and two heavily armed Muslims in California with possible ties to terrorism.

After Wednesday’s massacre in San Bernardino, Calif., which killed at least 14 people and wounded at least 21 others, Democrats redoubled their calls for stricter gun control laws. Party leaders moved Thursday to force Senate votes on measures to expand background checks for gun shows and online purchases and to prevent people on the terrorist watchlist from purchasing firearms.

“No matter what motivation these killers, these murderers, had, we can say one thing for certain: They should not have been able to do this,” Democratic presidential front-runner Hillary Clinton said Thursday while campaigning in Manchester, N.H. “I don’t believe we can stop every incident of gun violence, but we sure can stop a lot of them.”

But those votes failed amid opposition from the National Rifle Association and Republicans, who said the focus should be on tighter gun regulations, focusing instead on the need to step up antiterrorism efforts. President Obama said Thursday that the FBI had taken over the San Bernardino case because of possible terrorism connections.

Sen. Ted Cruz, R-Texas, plans to hold a “2nd Amendment” campaign event at an Iowa gun range Friday afternoon. (Susan Walsh/AP)

At a Republican Jewish Coalition forum Thursday, GOP candidates talked about being on a war footing and viewed the California shooting as a terrorist attack.

“When I heard about it, I figured probably not,” said Republican presidential front-runner Donald Trump. “But it turns out, probably related. Radical Islamic terrorism.”

Sen. Ted Cruz (R-Tex.) said that while details are still unclear, “all of us are deeply concerned that this is yet another manifestation of terrorism, radical Islamic terrorism here at home. Coming on the wake of a terror attack in Paris, this horrific murder underscores that we are in a time of war.”

Sen. Lindsey O. Graham (R-S.C.) seemed to echo part of Cruz’s remarks, saying, “I think the American homeland is part of the battlefield. I think we need to secure the homeland as if we’re at war, because we are.”

In an interview on MSNBC Thursday morning, former Maryland governor and long-shot Democratic candidate Martin O’Malley said the easy availability of guns played a key role in the tragedy.

“This may well be an act of domestic terrorism,” O’Malley said. “But it’s also one that’s made easier by the fact that we are the only developed nation on the planet that doesn’t do a damn thing to keep combat assault weapons out of the hands of those who should not be able to get them.”

Authorities identified Syed Rizwan Farook, 28, a county health worker who was born in the United States, and a woman described as his Pakistani-born wife, Tashfeen Malik, 27, as suspects. Both were killed in a shootout with police, and authorities are investigating whether the couple had any ties to radical jihadist groups.

“No matter what motivation these killers, these murderers, had, we can say one thing for certain: They should not have been able to do this,” Democratic presidential front-runner Hillary Clinton said Thursday while campaigning in New Hampshire. (Jim Cole/AP)

After the Colorado shooting, allegedly carried out by Robert Lewis Dear Jr., 57, many Democrats suggested that angry conservative rhetoric against Planned Parenthood fueled the environment in which the killings took place. Many Republicans have pushed to strip funding from Planned Parenthood because of activists’ claims that the organization illegally sells fetal tissue, an allegation denied by the women’s health-care provider.

Before it takes up the gun control votes Thursday, the Republican-controlled Senate will also consider measures to cut off Planned Parenthood funds.

After Wednesday’s shootings, GOP presidential candidates generally avoided any mention of gun safety regulations. Former Florida governor Jeb Bush said on Twitter that he was “Praying for the victims, their families & the San Bernardino first responders.” Former Arkansas governor Mike Huckabee said he was “Praying for those impacted by the shooting in California.” Trump said the shooting looked “very bad. Good luck to law enforcement and God bless. This is when our police are so appreciated!”

In another sign that Republicans are not going to budge in their defense of gun rights, Cruz plans to hold a “2nd Amendment” campaign event at an Iowa gun range Friday afternoon.

“This is still a 90/10 issue within the Republican Party,” former New Hampshire Republican Party chairman Fergus Cullen said about gun laws, adding: “All the intensity on the issue continues to be on the pro-gun side.”

Speaking to reporters Thursday, Obama said lawmakers need “to see what we can do to make sure that when an individual decides to do someone harm, we make it a little harder for them to do it. Because right now, it’s too easy.”

While campaigning, Clinton focused in part on barring people on the government’s no-fly list from being able to purchase weapons, as they can now.

“If you are too dangerous to fly in America, you are too dangerous to buy a gun in America,” she said.

But House Speaker Paul Ryan (R-Wis.) cast it as a Second Amendment issue.

“People are saying, you know, this no-fly list,” he said on MSNBC Thursday morning. “ ‘Don’t let a person who’s on a no-fly list get a gun.’ Well, there are people who arbitrarily placed on those things. Sometimes people are put on there by a mistake. And we would deprive of them of their constitutionally protected due-process rights.”

Ryan declined to speculate on the motivation behind Wednesday’s attack but said, “What we are working on right now, because there’s a common theme you see with many of these mass shootings, and that is the theme of mental illness. We have not updated our mental illness laws in decades. This is a problem because mentally ill people are getting guns and committing mass atrocities.”

By more than 2 to 1, more Americans believe mass shootings in the United States are more a reflection of problems identifying and treating people with mental illness than inadequate gun control laws, according to a Washington Post-ABC News poll taken in October. That poll also found the public split on whether to prioritize new laws aimed at reducing gun violence (46 percent) or protecting the right to own guns­ ­(47 percent).

For most attendees at the Republican Jewish Coalition conference, there was no question that the suspects in the California shooting had been radical Islamic terrorists.

“Just look at them — they just came back from Saudi Arabia,” said Dave Marshall, 76, a Philadelphia real estate developer who had done work in San Bernardino. “I don’t know if they screamed ‘Allahu Akbar’ or not, but it’s clear that they’re crazies.”

Ed O’Keefe, Scott Clement, Juliet Eilperin, Sarah Kaplan and Brian Murphy in Washington; Anne Gearan in Manchester, N.H.; and William Dauber in San Bernardino, Calif., contributed to this report.