SAN DIEGO (NEWS 8) - The race to replace Congressman Darrell Issa in the 49th District is expected to be a closely watched battleground in the midterm elections.

On Tuesday night, candidates vying for the seat gathered in North County to face some tough questions from high school students.

Early in 2018, Republican Rep. Darrell Issa, who represents coastal areas of San Diego County and part of Orange County, announced he would not seek re-election to Congress, where he has served 18 years.

Issa, the former chairman of the House Oversight Committee, narrowly won re-election in 2016 -- by just 0.6 percentage points against Democrat Doug Applegate -- and was widely considered the most vulnerable incumbent in the House going into the 2018 election. 

News 8's Richard Allyn reports from Carlsbad with some of the topics that were discussed.