If recent history shows, the candidates who received the Gov. Andrew Cuomo seal of approval for tomorrow’s primary elections will fare well.

Cuomo has waded in to a handful of Democratic Senate and Assembly primary races, notably backing Sens. Neil Breslin, Toby Stavisky and Adriano Espaillat.

This time last year, Cuomo had swooped in to several county executive and mayoral races across state, backing Democrats Mark Poloncarz of Erie County, Steve Bellone in Suffolk County and Mike Spano in Yonkers.

All defeated their Republican opponents.

In June, Cuomo endorsed in the Congressional primaries, backing Rep. Eliot Engel, Hakeem Jeffries and Nydia Velazquez.

They won, too (Rangel by a thin margin over Espaillat).

Cuomo, who enjoys a 70 percent approval rating, does not seem prepared to back the full slate of Senate Democratic candidates for a full takeover of the chamber, making his endorsements on a “case-by-case basis.”

Clearly, he’s not going to back the under-indictment Shirley Huntley, nor is giving aid to candidates who are likely to win.

But who he doesn’t endorse is just as important to note, too.

Breslin, for instance, is facing off against Shawn Morse, the Albany County legislator who is backed by the Independent Democratic Conference.

The IDC formed a PAC — which the foursome had said was equal parts defensive and offensive — and have doled out a considerable sum to Morse’s effort (though they are yet to show anything in the 24-hour filings).

There were also rumors that the IDC — led by Bronx Sen. Jeff Klein — would back Espaillat’s challenger Guillermo Linares and Manny Tavarez, who is trying to unseat Sen. Gustavo Rivera.

In the end, the IDC wound up backing Espaillat in his race.

For a twist (and perhaps to play with the Democratic conference’s collective anxiety) the IDC donated to Buffalo Sen. Tim Kennedy’s effort, only to have Kennedy insist he will stick with the remaining conference.

Should incumbents across the board carry the day, Klein’s math could be on Friday that he endorsed two-thirds of the winners, a line of thinking the Democratic conference would surely take issue with.

For Republicans, the calculus is different.

The three most closely watched primaries focus on challenges to Sens. Mark Grisanti, Roy McDonald and Steve Saland, who all voted “yes” for the same-sex marriage law last year (Sen. James Alesi is not running for re-election).

Saland, a Poughkeepsie Republican, probably is best in line to win tomorrow. McDonald faces Saratoga County Clerk Kathy Marchione, while Grisanti has a challenge from Kevin Stocker. Given the violatile nature of both races, it’s fair to call both potential toss ups, though the incumbents are spending a ton of cash to stay competitive.

Cuomo is not expected to endorse in these races. Even with a high marks from Republicans, an endorsement from the state’s top Democrat could ultimately back fire in a party primary.

The power of endorsements is difficult, if not outright impossible, to gauge.

“Coattails, endorsement, support, it’s hard to say,” said Quinnipiac poll spokesman Mickey Carroll. “I’ve always thought that it doesn’t make much difference. But particulary with the same-sex marriage, which was a big emotional issue, it will be interesting to see. As far as the governor’s impact, it will be interesting to see.”

“Is he doing very well or will he do very well for his legislative friends? I don’t know.”