In a result that could have a profound impact on the balance of power in the Empire State — and on Congressional and legislative redistricting — Democrat Craig Johnson won a special state Senate election on Long Island on Tuesday, breaking the GOP’s 100-year grip on the Senate district and putting Democrats within two votes of taking control of the Senate for the first time since the early 1960s.

State Senate Minority Leader Malcolm Smith (D) has told New York media outlets this week that he believes he can persuade two of his Republican colleagues to switch parties — something Majority Leader Joseph Bruno (R) vehemently disputes.

But with Democrats controlling the governor’s mansion and the state Assembly by a wide margin, the Senate becomes the major battleground as state pols look ahead to the next round of redistricting. The special open-seat Senate race cost a record-breaking $5 million, and it featured last-minute appearances from Sen. Hillary Rodham Clinton (D-N.Y.) and former New York Mayor Rudy Giuliani (R).

But it is new Gov. Eliot Spitzer (D) who is widely credited with Johnson’s win over Republican Maureen O’Connell. Spitzer implored voters to ratify his reform agenda by sending Johnson to Albany.

According to campaign finance records, Democratic Members of Congress were among the late donors to Johnson. Among them: Rep. Charlie Rangel (N.Y.) gave $5,000, and Reps. Howard Berman (Calif.), Carolyn Maloney (N.Y.) and Jerrold Nadler (N.Y.) gave $2,000 each. Maloney also gave $2,000 to the state Democratic Senate Campaign Committee.

Former state Republican Chairman Sandy Treadwell, who is contemplating challenging Rep. Kirsten Gillibrand (D-N.Y.), gave $8,500 to O’Connell in late January and another $10,000 to the state Senate Republican Campaign Committee.

— Josh Kurtz