(NewsNation) — Rep. Jake Auchincloss, D-Mass., encourages voters to focus on President Joe Biden’s “track record,” which he says is “superlative.”

“He rallied the free world to the defense of Ukraine,” Auchincloss said during a Monday appearance on “Elizabeth Vargas Reports.” “He put us in a stronger position relative to China for the first time in the 21st century. He has invested in infrastructure and manufacturing. The man has a lot to campaign on, and even if he is not as eloquent as he once was, those records speak for themselves.”

Earlier Monday, Biden reiterated in a letter to congressional Democrats that he’s not dropping out of the 2024 election despite recent calls for him to do so.

Writing in the letter that he’s had “extensive conversations” with party leadership, elected officials and voters over the past 10 days, Biden added they have “good faith fears and worries” about what is at stake in this election.

“Believe me, I know better than anyone the responsibility and the burden the nominee of our party carries,” Biden wrote.

However, “the question of how to move forward has been well-aired for over a week now,” Biden wrote. “And it’s time for it to end.”

Biden has fielded questions over whether he should be the Democratic nominee for president following a highly criticized performance at the first presidential debate two weeks ago. As he debated presumptive Republican nominee and former president Donald Trump, Biden stumbled through his words and appeared at times to be confused. Although Trump made multiple false statements during the debate, concerns over Biden’s age and mental fitness took center stage.

To Democrats in Congress, though, Biden wrote: “I wouldn’t be running again if I did not absolutely believe I was the best person to beat Donald Trump in 2024.”

“We have a historic record of success to run on,” Biden wrote.

NewsNation’s Kellie Meyer contributed to this report.