Story highlights Republicans say the southern U.S. border is vulnerable to Ebola and ISIS fighters

President Obama's administration says there's nothing to their concerns

GOP Rep. Duncan Hunter and candidates Scott Brown and Thom Tillis have pushed the issue

Two international crises are giving Republicans new reasons to break out a familiar rallying cry -- secure the border -- just weeks before the midterm elections.

A Liberian man's death in Texas from Ebola is triggering worries that the disease could spread beyond West Africa, while efforts by ISIS to recruit Westerners is stoking fears that its influence could reach into the United States. The seemingly disparate issues are gelling into a single talking point for Republicans arguing that weak border security is leaving the United States vulnerable.

The most direct link came from Rep. Duncan Hunter, who is sticking by his claim that at least 10 ISIS fighters were caught by border security officers trying to cross the United States' southern border.

On Thursday, the California Republican's spokesman, Joe Kasper, pointed to the Sept. 10 arrest of four people in Texas who "identified themselves, while in custody, as members of a specific, known-terrorist organization." He cited Homeland Security information "provided internally" about those suspects' claimed affiliations, saying they "met an individual in Mexico who spoke their own language and assisted in the smuggling attempt."

Kasper said the department's determination that those four aren't part of ISIS-linked groups is no surprise "because foreign nationals with terrorists associations, captured on the border, doesn't really play well for an administration trying to convince the world that the border is secure."

However, a U.S. government official who has reviewed the detention records said Hunter's claims are false. The official said the four men are Turkish and identified themselves as members of the Kurdish Workers Party, also known as the PKK, whose affiliates are the chief Kurdish group fighting ISIS in Syria.

The PKK is listed by the State Department as a terrorist group at the behest of Turkey's government, which has fought against a Kurdish insurgency for years. But the official said the men's links to terrorism were investigated and the Homeland Security Department concluded they don't pose a threat to U.S. national security.

Substantiated or not -- and no cases of Ebola have yet been identified in Central America -- linking Ebola and ISIS to border security is a way for Republicans to raise an issue that President Barack Obama and Democrats had sought to keep off the table until after November's midterm elections.

The president delayed his announcement on a long-awaited and politically-charged executive order dealing with illegal immigration until after the elections in an effort to keep from galvanizing the conservative base and handing Republican candidates a new club to whack endangered Senate Democrats.

But the international crises dominating news cycles less than a month from the midterms are giving Republicans a way to push the issue anyway.

Much of the criticism comes from Obama's most reliable opponents in Congress. But some Republican candidates -- including New Hampshire Senate hopeful Scott Brown -- are playing up their border security concerns on the campaign trail.

"If people are coming in from normal channels, can you imagine what they can do through our porous border?" Brown, the Republican challenging Democratic Sen. Jeanne Shaheen, told New Hampshire radio station WGIR on Thursday.

"It's so critically important to really use every tool, shut off every mechanism, for them and that disease and other potential diseases to come into our country," he said, adding that Shaheen has voted against GOP-backed border security measures and he wants to "call Sen. Shaheen out on that issue."

Thom Tillis, the Republican North Carolina House speaker who is challenging Sen. Kay Hagan, did just that during a debate Tuesday.

"Sen. Hagan has failed the people of North Carolina and the nation by not securing our border," he said. "Ladies and gentlemen, we have an Ebola outbreak, we have bad actors who can come across the border. We need to seal the border and secure it. We need to make it very clear that blanket amnesty is not on the table and then we need to solve for the first time in decades the problem we have with immigration in this country."

Also linking Ebola and ISIS to border security on Thursday was GOP Rep. Louie Gohmert of Texas. He told Newsmax that Obama and Secretary of State John Kerry believe climate change is "more deadly to this country than Ebola is climate change, more deadly than the Islamic State to Thomas Foley is climate change," in an apparent references to James Foley, a journalist who was beheaded by the group.

He said the reason the United States hasn't yet closed its borders is that Democrats want "everyone to feel included."

"Countries that recognize that they have an obligation to protect their people regardless of whether or not its politically correct have done just that," Gohmert said.

"We used to have quarantines of serious diseases that would kill people. But this day in time, gee, we don't want anybody to feel like they're being left out," he said. "So therefore some of my Democratic friends, including this president, they want everyone to feel included. So let's don't quarantine, let's don't close our borders."