Republicans are fast becoming an endangered species in New York’s Congressional delegation.

Democrats are aiming for a Yankee grand slam next week, hoping to pick up four more Republican seats to turn the delegation a deep-blue 27-2.

“When I first came to Congress there were 13 Republicans” in the delegation, said Rep. Tom Reynolds (R-N.Y.), who is retiring after a decade in the House and whose seat is in danger of falling into Democratic hands. “There are now six and coming out we’re likely somewhere between two to four.”

A blue tide has been washing over the state for the past two election cycles. In 2006, Democrats took back the governorship for the first time in 12 years and are now threatening to take the state Senate next week for the first time in 46 years — and that chamber’s flipping could have huge implications down the line for redistricting.

“The Republican Party has totally fallen apart and there’s a lack of leadership on a statewide level,” said a New York Republican consultant.

The consultant added that the anger of voters in downtrodden upstate areas pockmarked by closed factories makes for an unpredictable Election Day. “There is a lot of anger up there, and when people are angry, anything can happen.”

That has Democrats imagining a new era of dominance.

“The fact is the Republicans are a dying breed in the state of New York,” said Carrie James, a spokeswoman for the Democratic Congressional Campaign Committee.

Recent polls have shown Sen. Barack Obama (D-Ill.) blowing out Sen. John McCain (R-Ariz.) in the state at the top of the ticket, buoying Democratic hopes for coattails, although Republicans point to Democratic scandals, especially a financial scandal surrounding House Ways and Means Chairman Charlie Rangel (N.Y.), for comfort.

“Political fortunes can turn around quickly,” said Brendan Buck, spokesman for the National Republican Congressional Committee. “With the dean of their delegation under formal investigation and their governor stepping down in disgrace, Democrats shouldn’t be so quick to assume they have won the trust of New York voters.”

Campaign operatives in both parties, however, acknowledge that two Republican seats likely to flip are the central New York 25th district seat held by retiring Rep. Jim Walsh and the Staten Island seat being vacated by Rep. Vito Fossella after his drunken-driving/love child scandal.

Republicans have written off the Fossella seat entirely after a messy primary, with New York City Councilman Mike McMahon (D) expected to topple former state Assemblyman Bob Straniere (R) and eliminate the last Republican seat in New York City.

The GOP also acknowledges an uphill battle in the Syracuse-based 25th, where former Congressional aide Dan Maffei (D) has vastly outraised former Onondaga County Legislature Chairman Dale Sweetland. Maffei, who worked for then-Sens. Daniel Patrick Moynihan (D-N.Y.) and Bill Bradley (D-N.J.) and the House Ways and Means Committee, narrowly lost to Walsh in 2006.

Democrats are also waging battles in two more upstate districts that have been reliably Republican in the past. Polls have shown Rep. Randy Kuhl facing a tough battle to keep his Southern Tier/Rochester-area seat against retired Navy officer Eric Massa (D) in a rematch of 2006, when Massa came within 2 points of victory in the conservative-leaning 29th district.

“This is probably our best chance,” said a GOP operative, noting that the NRCC has been pumping some of its limited resources into the district to defend Kuhl. “They’ve gone in there and they are hitting Massa pretty hard.”

And in the western New York 26th district, where Reynolds is retiring, self-funded businessman Chris Lee (R) and lawyer Alice Kryzan (D) are facing off, after Kryzan won a surprising primary victory against better-funded opponents.

Democratic heavyweights, including Sens. Hillary Rodham Clinton (N.Y.) and Charles Schumer (N.Y.) and House Majority Leader Steny Hoyer (Md.), are planning swings through upstate New York this week, and the DCCC has poured cash into the upstate races as well, including $1.5 million into Kryzan’s race alone.

That seat remains the hardest to handicap because both candidates are new and so much cash is flowing in at the end.

Another wrinkle is that one of Kryzan’s primary opponents, Jon Powers, will appear on the ballot under the Working Families Party line despite having moved out of state, Reynolds noted. Powers has endorsed Kryzan and is campaigning with her, but nonetheless his place on the ballot could still siphon off a few precious votes.

Republicans, meanwhile, have had high hopes for one challenger, Sandy Treadwell, the former New York secretary of state and state GOP chairman who is pouring his own money into his race to defeat freshman Rep. Kirsten Gillibrand (D). But Gillibrand has been one of the most prodigious fundraisers of any incumbent this year and is favored to hold on.

Republicans in general acknowledge a difficult environment with an unpopular president, and they can only look to the possibility of a backlash year in 2010 — assuming that Obama wins the presidency.

“Things are looking up two years from now with people who are traditionally limited government folks, who aren’t going to like what they will probably get from a Democratic president,” the GOP operative said.