Sen. Cory Booker calls 2018 midterms 'a check or a balance' for Trump The Democrat said the midterm may be the most important of his lifetime.

Sen. Cory Booker isn't up for re-election this year, but he still says this could be the most important midterm election of his lifetime.

In an interview with Stephen Colbert on Tuesday, the New Jersey Democrat said the 2018 midterm election is crucial for a number or reasons, but mainly because it'll serve as “a check or a balance” to President Donald Trump.

“We have a lot of controversial races across the country,” he said. “This is said often, but this is probably the most important midterm election in my lifetime in terms of giving a check or a balance to a president right now who has control of the House and the Senate.”

Booker, a vocal critic of Trump, also made the case for why his party needs more congressional power.

“We need to make sure that, in my opinion, that we get more Democrats elected so we can start providing more of a check and balance to what we see happening,” Booker said.

The senator wouldn’t say if he planned to run for president in 2020, but said he’s definitely planning to run for some sort of office soon.

“So what you know, and the audience doesn't, is I'm up for re-election as a United States senator in 2020, so I will be running in 2020,” he joked.

Democrats would need to win at least 24 seats to gain a majority in the House, where at least 41 Republicans are planning to retire, resign or run for another office, according to an analysis by ABC News.

Control of one chamber on Capitol Hill would give Democrats the power to block the Republican agenda and use their majority power in the respective congressional oversight committee to launch investigations into the White House.