Republican leaders had ticketed Thom Tillis as their best hope to unseat incumbent North Carolina Sen. Kay Hagan -- but a month before voters go to the polls Tillis still is trailing, and his campaign is cranking up its attacks on Hagan's Senate record by questioning her national security credentials in light of the growing Islamic State threat.

Tillis, the state House speaker, is turning up the heat in the final weeks. He's bringing in party luminaries for campaign cameos, including former Florida Gov. Jeb Bush last week. And he's hitting his Democratic opponent hard on foreign policy -- specifically, how one of the world's fastest-growing terror groups went largely ignored by lawmakers in Washington.

On Monday, Tillis’ camp released a new 30-second ad that hammers Hagan for missing several Senate Armed Service Committee hearings while the Islamic State threat mounted. It accuses Hagan of missing half the committee hearings this year, suggesting both she -- and President Obama -- were sitting back at a critical time.

“While ISIS grew, Obama kept waiting and Kay Hagan kept quiet,” the narrator says ominously. “The price for their failure is danger.”

Hagan’s camp, which had been relatively quiet on the topic, hit back Monday – saying that Tillis’ new ad “attempts to distract from his own record by distorting Kay’s instead.”

But Tillis' approach effectively seizes on a growing national anxiety about the rise in terror groups, which is becoming a factor in races that used to focus on health care and the economy.

During a recent stop in Charlotte, Tillis and Sen. Lindsey Graham, R-S.C., hammered home the message that Hagan and Obama are to blame for the growing emergency linked to extremist groups like ISIS and said a new approach in Washington is needed.

"Anything short of a strategy that calls for and achieves the complete elimination of ISIS and any emerging threats is unacceptable," Tillis said in an interview with FoxNews.com.

He added, "I think this president needs to recognize that he, more than anyone else, needs to get that right and the senator that I'm running against, Kay Hagan, needs to start playing a more active role and demanding that we have a comprehensive strategy to what's occurring the Middle East."

Tillis accused Hagan of siding with Obama and helping give rise to ISIS by their “inaction and appeasement.”

The GOP nominee, though, was unclear when asked what he would do in Hagan's position. He said only that his decision would be based on what military officials told him and that as a “private citizen” he could not comment on what he’d do or how he’d vote.

When asked about the prospect of arming Syrian rebels, Tillis said he wasn’t sure if it was a good idea to arm them, saying he would “have to know that these arms would not get in the hands of people who would want to take over the Middle East.”

Sadie Weiner, Hagan’s communication director, ripped Tillis for not saying what he would do. “North Carolinians – especially our servicemembers and their families – deserve better than Speaker Tillis’ spineless fence-sitting on this pressing national security threat,” she said.

Andrew Taylor, professor of political science at North Carolina State University, also said such responses by Tillis could backfire with voters.

But he nevertheless said the Tillis tactic of painting Hagan as “an out-of-touch, ineffective” politician could generate the bump the GOP nominee needs on Election Day.

“Tillis has been doing this for awhile and really going after Hagan as someone who isn’t a principle player in Washington and isn’t at the table when important decisions are being made,” Taylor said.

Recent Fox News and other polls show Hagan slightly ahead. The Fox News poll showed Tillis leading by 5 points; a separate CNN/Opinion Research poll put her ahead by 3 points. Both surveys had a margin of error of 4 percentage points.

Republicans need to pick up a net six Senate seats to gain control of the chamber next year. With once-sleepy races like Kansas suddenly looking competitive for Republicans, it makes states like North Carolina all the more important for the GOP. In the closing weeks, both parties are pulling out the stops, sending heavy-hitters into the state to stump for their respective nominees.

Last week, Tillis campaigned with New Jersey Gov. Chris Christie, South Carolina Gov. Nikki Haley and Bush. Former President Bill Clinton will be a special guest Tuesday during a Hagan luncheon in Chapel Hill.

The Senate race in North Carolina also has seen a staggering amount of outside money pouring in, with some experts predicting it will be one of the most expensive Senate races in history.

The candidates' most recent campaign finance filings showed Hagan ahead with $8.7 million in cash on hand and Tillis with $1.5 million. According to the Center for Responsive Politics, more than $22 million has been spent in outside money in North Carolina for the midterm races, with the majority going to the Senate race.