Election Day this year could hand Democrats control of the last lever of power in New York state government now (barely) in the hands of Republicans: the state Senate.

With 31 of the 63 seats in GOP hands, Republicans now control the Senate thanks only to the support of Sen. Simcha Felder — a Brooklyn Democrat who’s told his constituents he’ll align with whichever party he thinks is best for his district.

Mayor de Blasio has long pushed for the Democrats to regain the Senate, raising big bucks for their campaigns — because a Democratic Senate would deliver his “progressive” agenda on steroids:

New laws to handcuff cops and give criminals even more get-out-of-jail-free cards.

The state’s highest-in-the-nation taxes would soar higher still, to feed public-sector unions and other special interests.

Businesses across the state would get walloped with new laws mandating ever-higher pay and benefits. Jobs would flee even faster than they already are.

No, the Senate Republicans aren’t angels; they, too, make bad deals with unions and other special-interest groups. But they’re the only brake on runaway liberal rule.

Here are The Post’s picks for Senate:

Senate District 5 (Nassau/Suffolk): Education Committee Chairman Carl Marcellino is a pillar of the Senate’s GOP caucus. A former science teacher, he has stood up against de Blasio’s attacks on charter schools. The Democrat, Jim Gaughran, who has served as a Suffolk lawmaker and Water Authority chairman, has a record of backing tax hikes. Marcellino is the better choice.

SD 6 (Nassau): Republican Kemp Hannon, chair of the Health Committee, is an Albany institution — widely respected for his intellect, particularly on health-care issues. He’s also fought hard for tax cuts. Hannon faces a challenge from Democratic lawyer Ryan Cronin, who’s gotten big financial support from two pro-de Blasio unions. Hannon deserves to keep his seat.

SD 37 (Westchester): Julie Killian (R) would bring a breath of fresh air to this district by beating 12-year Democratic incumbent George Latimer. The Rye city councilwoman, who holds a degree in chemical engineering and an MBA, believes (rightly) that onerous regulations and high taxes are strangling businesses and jobs. She favors a permanent cap on property-tax hikes. Latimer voted against the cap in 2011.

SD 39 (Orange, Ulster, Rockland): Incumbent Bill Larkin (R) served in the Army for 23 years, reaching the rank of lieutenant colonel. A dedicated fighter for veterans and for his community, he’s facing a strong challenge from Orange County lawmaker Chris Eachus (D) — a pawn of the teachers unions. New York needs Larkin to hang on to his seat.

SD 40 (Westchester, Putnam, Dutchess): Republican Sen. Terrence Murphy, a chiropractor and small-business owner, has fought hard to extend the property-tax cap. (West­chester is among the highest-taxed counties in America.) He has also focused on combating the heroin epidemic. He’s a far better pick than yoga instructor and Pound Ridge town board member Alison Boak (D).

SD 41 (Dutchess, Putnam): Sen. Sue Serino (R), another small-business owner, is the clear choice here. She has pushed for middle-class tax cuts and understands first-hand the horrors of state-imposed red tape on businesses. And she refuses to take a penny in per diem pay when in Albany. Her opponent, Democrat Terry Gipson, took funds solicited by de Blasio & Co. in 2014 in a scheme now under investigation.