WASHINGTON, D.C. -- Former secretary of state and Democratic presidential front-runner Hillary Clinton made a highly anticipated appearance Thursday before a House Committee investigating the 2012 attack on the U.S. diplomatic compound in Benghazi, Libya.

On the night of Sept. 11, 2012, terrorists overran a U.S. diplomatic compound in Benghazi. Four Americans died in the attack, including U.S. Ambassador Chris Stevens.

The hearing began with an aggressive defense of the panel’s work by its chairman, Rep. Trey Gowdy.

"This investigation is about four people who were killed representing our country on foreign soil," said Gowdy, R-South Carolina.

Gowdy and the committee’s six other Republicans said the former Secretary of State failed in her duty to safeguard the consulate.

"Why were there so many requests for more security personnel and key equipment and why were those requests denied in Washington?" Gowdy asked.

"Those requests and issues related to security were rightly handled by the security professionals in the department," said Clinton. "I did not see them, I did not approve them, I did not deny them."

The committee's Republicans also criticized Clinton for using a private email server to conduct official State Department business.

One even used a prop to showing the large number of emails Clinton sent about Libya and Benghazi after the attacks versus the smaller number she sent before.

"There are 795 emails in this pile. We've counted them. There are 67 e-mails in this pile in 2012, and I'm troubled by what I see here," said Rep. Susan Brooks, R-Indiana.

“Well, congresswoman, I did not conduct most of the business that I did on behalf of our country on email," Clinton said.

With a presidential election set for 2016, Democrats say this Benghazi hearing is political theater, and they point to an unguarded comment by House Majority Leader Kevin McCarthy as proof.

"As well know, Rep. Kevin McCarthy admitted that they established this select committee to drive down Secretary Clinton's poll numbers," said Rep. Elijah Cummings, D-Maryland.

In the end, Thursday's hearing rehashed many of the same debates from previous congressional hearings.

Democrats are hoping Clinton’s testimony will put the issue to rest, once and for all.