The decision of embattled New York Governor David Paterson to quit his bid for a full term is exceptionally good news for Democrats–not just in New York but nationally.

Rocked by scandals, including the recent revelation that he had personally meddled in a domestic violence dispute involving a top aide, the governor decided to drop his 2010 bid–although, according in the he will not resign the governorship.

"I am being realistic about politics," Paterson explained. "Today I am announcing that I am ending my campaign for governor of the state of New York."

This is a personal tragedy for Paterson, who has struggled personally and politically since assuming the governorship of former Governor Eliot Spitzer, who was forced to resign after getting wrapped up in a prostitution scandal.

It is, as well, a tragedy for the Paterson family, which had been at the forefront of New York Democratic politics since the current governor’s father, Basil, was one of the first African-Americans to earn a top spot on a statewide ticket in the country. (Basil Paterson was the Democratic nominee for lieutenant governor in 1970 and served as New York Secretary of State. He remains an epic, and active, figure in New York labor, civil rights and political circles.)

Just about everyone in New York Democratic politics would have liked to see Basil Paterson’s son make a success of the state’s top job. But his tenure has been plagued by budget crises, political stumbles and personal conflicts. And his decision to seek a full term unsettled Democrats who may have liked the governor personally but did not like his prospects politically.

Thus, for New York Democrats–who faced the prospect of a bruising primary fight between Paterson and Attorney General Andrew Cuomo, which might in turn have weakened the eventual Democratic nominee in what is shaping up as a tough year for Democrats in every state–Paterson’s exit is anything but a tragedy.

Cuomo, the son of former Governor Mario Cuomo, is well positioned to make the gubernatorial run, with good prospects of winning the primary and general election.

That’s important for Democrats in New York because, though New York is a blue state, it has a history of electing Republicans to the governorship–especially in years when national trends favor the GOP. Having a strong candidate at the top of the ticket should benefit Democratic prospects in the race to fill Secretary of State Hillary Clinton’s old U.S. Senate seat (where appointed incumbent Kirsten Gillibrand could face tough primary and general election challenges) and a number of marginal House seats where recently-elected Democrats will struggle this year to retain formerly Republican seats.

Perhaps, most importantly, a strong showing for New York Democrats in 2010 will put them in a good position when it comes time to redrawing congressional districts in a state where redistricting has historically provoked bitter partisan wrangling.

The 2010 gubernatorial races–as well as state legislative contests–will define the direction of redistricting nationally. And the drawing of district lines remains the most definitional force in our politics, even more meaningful than money or the personal appeal of particular candidates.

In the absence of the sort of redistricting reform that would foster honest competition — as opposed to the current system that allows politicians to use the map-drawing process to reduce and even eliminate competition in some states — it matters who controls the statehouse when fresh census figures arrive. And it matters particularly in New York state, where Democrats have in recent years claimed a half dozen suburban and upstate seats that used to be considered reliably Republican. Many of those districts remain highly competitive and the redistricting process could well determine whether they tip to one party or the other.

With national Democrats worrying more and more about not just the 2010 election cycle but the redistricting fights of 2011 in key states such as New York, Paterson’s exit will inspire some sadness for an overwhelmed man and his family. But there will, as well, be a great sigh of relief at the news that their prospects for retaining the upper hand in New York politics have just improved–dramatically.