Longtime Democrat Sen. Ben Cardin said he won't seek reelection, clearing a path for a new face to join the Senate.

"I am proud of all I have done for Maryland. I have given my heart and soul to our great state, and I thank Marylanders for trusting me as your representative for all these years. Thank you, Maryland," Cardin tweeted Monday, sharing a video of his retirement announcement. 

In video message with his wife, Myrna, Cardin recalled it’s been 56 years since he first ran for office. 

"You know, Myrna, it’s been the honor of my life to represent the people of Maryland first in the Maryland General Assembly, then as speaker of the House, later as a member of the House of Representatives, and now as a United States senator," Cardin said. "When this term ends, it will be my last year as an elected official. I will not seek reelection." 

DEM SENATOR ACCUSES TRUMP OF LEAVING BIDEN WITH ‘BAD OPTIONS’ FOR DISASTROUS AFGHANISTAN WITHDRAWAL 

Ben Cardin shakes hand in Senate chamber

Ben Cardin says he will not seek another term in the Senate. (Chip Somodevilla / Getty Images / File)

"It’s time," Cardin, 79, told the Baltimore Sun in an interview at his Pikesville home. "I always knew this election cycle would be the one I would be thinking about not running again, so it’s not something that hit me by surprise. I enjoy life. There are other things I can do."

"Democrats are quickly realizing that the Senate won't be any fun for them when Republicans retake the majority in 2024," National Republican Senatorial Committee spokesperson Tate Mitchell told Fox News.

Cardin has served in the Senate since 2006, when he won a seat to replace retiring Democrat Paul Sarbanes. Before that, he was a congressman who represented a large part of Baltimore and several nearby suburbs, winning his first U.S. House race in 1986.

Sen. Ben Cardin on Capitol Hill

"I am proud of all I have done for Maryland. I have given my heart and soul to our great state," Sen. Ben Cardin said. (AP Photo / Mariam Zuhaib / File)

Monday's announcement sparked speculation that former Maryland Gov. Larry Hogan, a Republican, could run for Cardin's seat.

But a source close to the former two-term governor reiterated to Fox News on Monday afternoon that Hogan "has never been interested in the Senate." 

Longtime Senate GOP leader Mitch McConnell and his allies encouraged Hogan to campaign for the Senate in 2022 - when Democratic Sen. Chris Van Hollen successfully ran for re-election - but the then-governor resisted the aggressive recruitment push.

LARRY HOGAN SLAMS TRUMP AFTER DECLINING 2024 BID: GOP MUST AVOID 2016-STYLE CANDIDATE ‘PILEUP’

Democrats hold a razor-thin 51-49 majority in the Senate but are defending 23 of the 34 seats up for grabs next year - including three in reliably red states and a handful in crucial general election battlegrounds. But that's not the case in Maryland, a heavily blue state.

"Democrats are quickly realizing that the Senate won't be any fun for them when Republicans retake the majority in 2024," National Republican Senatorial Committee spokesperson Tate Mitchell said in a statement.

During his tenure in the Senate, Cardin has taken a mostly liberal stance in advocating on health care, retirement security, the environment and fiscal issues. The senator has also been a leading advocate for clean water and the Chesapeake Bay, the nation’s largest estuary, which flows through his home state.

He helped write the Paycheck Protection Program that helped small businesses in Maryland and nationwide endure the economic impact of the COVID-19 pandemic. He also created the Economic Injury Disaster Loan Advance Grant program to quickly get cash to small businesses in need.

Sen. Ben Cardin in front of Capitol building

Sen. Ben Cardin announced the end of his decades-long career in elected office. (AP Photo / J. Scott Applewhite / File)

His legislation to expand Medicare to include preventive benefits such as colorectal, prostate, mammogram and osteoporosis screening was also enacted.

"I salute my friend and our state’s senior Senator Ben Cardin on his extraordinary public service to Maryland and our country," Sen. Chris Van Hollen of Maryland said in a statement Monday. "It is a privilege to serve alongside him and in partnership every day for the people of our great state."

CLICK HERE TO GET THE FOX NEWS APP

Cardin also has worked in foreign affairs, supporting the integration of anti-corruption, transparency and respect for human rights into foreign policy. He chaired the Commission on Security and Cooperation in Europe, also known as the U.S. Helsinki Commission.

Cardin counts among his achievements the passage of his legislation to increase the amount Americans can put into their 401(K) plans and IRAs, which was enacted in 2001.

Fox News' Paul Steinhauser and the Associated Press contributed to this report. This is a developing story. Check back for updates.