Mandel, who currently serves as the Ohio state treasurer, made the announcement last week over his wife's health issues.
"We recently learned that my wife has a health issue that will require my time, attention and presence. In other words, I need to be there," Mandel said in an email. "Understanding and dealing with this health issue is more important to me than any political campaign."
RELATED: Rising political stars to watch in 2018
Rising political stars to watch in 2018
Rising political stars to watch in 2018
Randy Bryce (D)
Bryce made waves earlier this year when he announced he would run against House Speaker Paul Ryan in the 2018 midterm elections. Bryce, a Democrat, is a U.S. Army veteran, cancer survivor and union ironworker.
Rep. Scott Taylor, (R-VA)
A former Navy SEAL, Taylor has represented Virginia's 2nd District since he was elected in 2016. He has branded himself as a Republican lawmaker who is unafraid to speak out against President Trump and members of his own party -- recently calling out Roy Moore for allegations of sexual misconduct.
Rep. Seth Moulton, (D-MA)
39-year-old Seth Moulton has increasingly emerged as a prominent House member and one to watch within the Democratic party. He served four tours of duty in Iraq and notably serves as the. Recently, he has advocated for "a new generation" of Democratic leadership.
Rep. Chris Collins, (R-NY)
Collins was elected to represent New York's 27th district on Capitol Hill in 2012, and has since positioned himself as a vocal right-wing defender within the Republican party. He also came out as one of President Trump's most vocal supporters leading up to an after the 2016 election.
Rep. Raja Krishnamoorthi (D-Ill.)
Krishnamoorthi was elected in 2016 -- making him one of the more freshman lawmakers on Capitol Hill. Still, the former lawyer with a past of aiding the Obama administration has played an integral role this year in congressional investigations into the Trump campaign's potential ties to Russia. As a member of the House Committee on Oversight and Government Reform, he has taken many opportunities to speak critically of the clearance aides like Jared Kushner have -- and has firmly positioned himself as a staunch opponent of GOP efforts to repeal and replace Obamacare.
Sen. Lisa Murkowski, (R-AK)
As one of 21 women currently serving in the U.S. Senate, Murkowski has positioned herself as a more moderate leader within the Republican party. Murkowski refused to toe the party line on an attempted Obamacare repeal earlier this year, and has since raised skepticism over specific elements of the GOP tax bill and Republican Senate candidate Roy Moore.
Rep. Charlie Crist, (D-Fla.)
Crist is one of the more interesting players currently positioned in the political landscape. Once a Republican, Crist served as both attorney general and governor of Florida -- but then switched to a member of the Independent and eventually Democratic party. In his current House role representing Florida's 13th congressional district, Crist has emerged as a Democrat unafraid to take a middle-ground approach in his policy stances.
Sen. Tom Cotton, (R-AR)
As the youngest U.S. senator, Cotton's political future currently looks very bright. As one of the few Capitol Hill lawmakers that has yet to have a public feud -- on Twitter or otherwise -- with President Trump, Cotton was recently on the shortlist to replace Mike Pompeo as CIA director if Pompeo replaced Rex Tillerson as secretary of state.
Sen. Catherine Cortez Masto, (D-NV)
Catherine Cortez Masto is the first Latina ever elected to the U.S. Senate.
Governor-elect Ralph Northam (D-VA)
Northam was elected governor of Virginia in the series of "anti-Trump" Election Day victories Democrats celebrated in Nov. 2017. Northam's victory over Ed Gillespie signaled a potential shift in the oft-fraught over Virginia battleground state -- and Northam's gubernatorial tenure will be one to eye in the context of midterms and the 2020 presidential election.
Sen. Kirsten Gillibrand (D, NY)
Many who watch politics closely have noted Gillibrand as one to watch since she was appointed to Hillary Clinton's former Senate seat in 2009, and then elected in 2012. Early in her Senate career, Gillibrand used her position as a member of the Committee on Armed Services to chalk up a major legislative win by championing the repeal of "Don't Ask, Don't Tell." Gillibrand has also recently spoken out against sexual harassment allegations stemming from both Democratic and Republican offices -- calling on both Sen. Al Franken and President Trump to resign.
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Vance grew up in the Rust Belt Ohio town of Middletown and detailed both his upbringing and the experiences that come with Appalachian poverty in his 2016 literary release.
While McConnell may have reached out to Vance, others may be more skeptical of a campaign from the Yale Law School graduate who has been critical of President Donald Trump in the past.
As a CNN contributor, Vance has said that Trump's rhetoric is not in the best interest "of the party or the country."
WATCH: Best-selling author J.D. Vance opens up about his painful childhood: