(CBS) — It’s the first one-on-one debate in one of the most closely-watched senate races in the country.

GOP incumbent Mark Kirk faced off against Democratic challenger Tammy Duckworth at the Chicago Tribune editorial board.

READ MORE: FDA Approves Pfizer-BioNTech COVID-19 Vaccine For Children Ages 12 To 15

CBS 2 Political Reporter Derrick Blakley was there.

From the start, U.S. Sen. Mark Kirk framed himself as an independent who placed principles over party.

“I have sought to be the glue in the Senate to make sure that things happen,” Kirk said Monday.

But Duckworth attacked Kirk, saying he should have refused to vote for GOP Senate leaders who denied a confirmation hearing to President Obama’s U.S. Supreme Court nominee.

“We can’t just have pictures taken with him and then do nothing about it like the incumbent senator has done,” she said.

The two also tussled over Syrian refugees.

READ MORE: Navy Pier Flyover Completed After Years Of Construction Delays -- Many Ask Why It Too So Long

Kirk proposes a safe haven in Jordan protected by U.S. Navy pilots. Duckworth stopped short of endorsing that idea.

While Duckworth endorsed free community colleges, Kirk says the numbers don’t add up.

“They asked her three times, what is the cost of this program? She couldn’t answer,” he said.

Duckworth blasted Kirk over his penchant for bizarre comments.

“What would you call it when you have a man who calls his senate colleague a ‘bro with no ho’?” Duckworth said.

Replied Kirk: “If I have too quick a turn of phrase, that’s just my bad.”

MORE NEWS: Buckingham Fountain To Be Turned On Before Memorial Day After Sitting Dry For Over A Year Amid Pandemic