Washington ( CNN ) -- Sen. Kay Hagan 's campaign said late Wednesday the North Carolina Democrat missed a classified hearing last winter on the threat from the terrorist group ISIS to go to New York to raise money for her re-election . Hagan admitted earlier this week she did n't attend a hearing because she went to the fundraiser but did n't disclose which hearing she missed . Her decision to skip the Armed Services Committee session -- at which high-level administration intelligence officials filled in senators on top secret details about the group -- is drawing fire from her Republican opponent , North Carolina House Speaker Thom Tillis , who is narrowly trailing her in recent polls . The Feb. 27 , 2014 classified ISIS hearing she missed adds to a long list of Armed Services Committee hearings Hagan has already acknowledged skipping . Her aides had previously explained she missed 27 of 49 public hearings over the last two years because of scheduling conflicts with other Senate business , such as hearings for different committees and meetings with North Carolina constituents . Tillis is betting her absences from the national security hearings will hurt the first-term senator 's re-election effort in the Republican-leaning Tar Heel state -- which has a very large military population -- even though he too has faced criticism for missing work in the state capital in order to attend his own fundraisers . `` There is nothing more important than receiving briefings on our national security , '' Tillis told reporters on a conference call Wednesday . `` It 's the top responsibility of every Member of Congress . Senator Hagen has failed to do her job . What is her excuse for not showing up to work over half the time ? '' Tillis released an ad on Thursday slamming Hagan for missing hearings . Charges that incumbents have missed hearings , briefings , votes , and other official work are popping up in a several closely-fought Senate races this year . The notion that lawmakers are not showing at the jobs they were elected to do infuriates many voters and feeds a narrative that Washington is broken and office holders need to be replaced . Democratic campaign operatives in Washington , who are already battling headwinds in their effort to keep the Senate in Democratic control , conducted private polling on the question so they could fully understand its impact . The results showed the issue is very potent and could damage even seasoned candidates . Senate math seems impossible to some Democrats . In this year 's midterm campaigns , Republican challengers have accused Democratic senators Mark Udall of Colorado and Jeanne Shaheen of New Hampshire of missing hearings related to the threat from the terrorist group ISIS . Rep. Bruce Braley , the Democratic candidate for Senate in Iowa , faced a barrage of TV ads accusing him of not appearing at hearings on the Veterans Administration 's recent health care scandal . `` When our veterans needed him , Bruce Braley was AWOL , '' one TV ad this summer charged . In another tight race , Kentucky Democratic Senate candidate Allison Grimes blasted Senate Republican Leader Mitch McConnell for missing hearings of the agriculture and appropriations committees and suggested he was too busy with his leadership duties to deal with the needs of Kentuckians . The allegations that Hagan missed so many Armed Services Committee hearings first came to light last month . But at a news conference Tuesday night , following a debate with Tillis , Hagan was asked directly , `` Did you miss any of these meetings specifically for a fundraiser ? '' `` You know , there was one , '' she responded . `` And what had happened at that hearing , it was scheduled early in the day . And then votes were scheduled , and that hearing then had to be postponed later that day . So , yes , I did miss that one . '' The fact that she skipped such an important hearing , at which the Director of National Intelligence James Clapper and the Director of the Defense Intelligence Agency took questions from senators on `` current and future worldwide threats to the national security of the United States , '' according to the committee website , could prove politically difficult for voters to understand . On his conference call , Tillis was asked about why he missed work in the North Carolina House to raise campaign cash . He deflected the question but said , `` Quite honestly , if I had anything approaching the seriousness of the threat of ISIS , I would have canceled anything I was doing . '' DSCC ad : Tillis in Koch brothers ' pocket . Whether voters will accept Hagan 's and Tillis 's explanations remains to be seen . But one of the dirty little truths about the way Washington works is that lawmakers from both parties have very busy schedules and do n't attend all the hearings of the committees and subcommittees to which they are assigned . Even veteran senators from safe states will bristle at the suggestion they might have skipped a national security hearing or classified briefing to attend something that could be perceived as political in nature . That 's because they 've learned that voters do n't take it lightly .
Sen. Kay Hagan 's admission might hurt her chances at re-election . Republican challenger Thom Tillis says Hagan `` failed to do her job '' Similar charges have been made ahead of hard-fought midterms .