Almost a decade of Republican dominance of Congressional redistricting could be wiped out today.

After the 2000 Census and redrawing of Congressional lines for the 2002 election cycle, Republicans ran the table and won all three “fair fight” districts — seats that weren’t gerrymandered heavily in favor of either party and were drawn so that a Democrat or Republican could win.

But when today’s votes are counted, Democrats could hold all three.

Democrats already won Colorado’s 7th district when it became vacant in 2006. Today, the focus is on Nevada’s 3rd district, where Rep. Jon Porter (R) faces his most difficult re-election since winning the seat in 2002, and Arizona’s 1st district, an open seat being vacated by indicted Rep. Rick Renzi (R). Democrats are favored to win the Arizona seat, and Porter’s re- election is considered a tossup.

Republicans were widely viewed as the overall winners of the 2002 redistricting battle, and they maximized their Congressional gains in the 2002 and 2004 elections.

After the 2004 contests, House Republicans held 232 seats — the most since the Eisenhower administration.

But that advantage was wiped out by the Democratic tidal wave that swept the country in 2006, and depending on the size of the Democratic wave this year, Republicans may find themselves trying to dig out of a much deeper hole in the 2010 elections — one cycle removed from the next round of redistricting.

If Democrats control all three seats in the next Congress, it will be due to a variety of factors. Still, the loss of those seats and others would be emblematic of GOP’s current woes and of how far the party has fallen since talk earlier this decade of creating a permanent majority that would be impenetrable for years.

In 2006, some districts switched hands because Republican map makers carved too much from the districts of otherwise politically safe incumbents in an attempt to maximize their gains in 2002, making it very difficult for those Members to withstand a partisan wave.

“I call it holding everyone’s head just above water,” said Gerry Hebert, a Democratic redistricting expert and attorney. “Of course it doesn’t take much of a tide change for everyone to drown.”

The same could also be true this cycle, along with the fact that other Members have simply fallen prey to demographic changes that have taken place over the past eight years.

Porter falls into the latter category as his district has seen a massive influx of new voters in recent years and has been steadily trending toward Democrats.

Pennsylvania was a good example of a state where GOP attempts to draw new districts for Republicans in 2002 came back to haunt the party in 2006. Last cycle, Democrats there picked up four House seats — the most of any state — as well as a Senate seat.

This cycle’s best example of the 2002 redraw coming home to roost could be Florida, where Republicans have dominated the delegation for much of the past two decades and where four Republican incumbents are in difficult re-election fights.

Two of those Republicans, Reps. Tom Feeney and Mario Diaz-Balart, were first elected to newly created districts drawn specifically for them in 2002.

Feeney’s re-election prospects look grim, but that has as much or more to do with fallout from his ties to the Jack Abramoff lobbying scandal than it does the changing demographics of his Orlando-area seat.

Diaz-Balart’s south Florida district has also seen demographic changes and an influx of non-Cuban Hispanics.

Rep. Ric Keller (R-Fla.) is also in a difficult race. Republicans slightly improved the GOP performance of his Orlando-based district in the last round of redistricting, but they did not alter it as much as they could have because GOP legislators were seeking to carve two new Republican districts. The area has also seen rapid growth and voter registration changes since then.

Still, even if Democrats were to win all four of the competitive GOP-held seats in Florida, they would control just 12 of the state’s 25 seats, provided scandal-plagued Rep. Tim Mahoney (D-Fla.) loses re-election, as expected.

Along with a projected double-digit pickup of House seats, Democrats could also gain majority control of a few more Congressional delegations after today’s elections.

Democrats currently hold a majority of House seats in 27 state delegations, while two states are evenly split between the parties.

Why does the makeup of delegations matter when it comes to redistricting?

In most states, the legislature is responsible for the redrawing of district boundaries and the plans must be approved by the governor. Still, in many states the Congressional delegation holds great sway over the process, and in many cases, the delegation members will agree to strike a deal — generally one that protects incumbents. Having more weight in more Congressional districts could help Democrats have more influence in the lines that will be drawn four years from now.

There are a number of key states, from a redistricting standpoint, where Democrats could gain a majority of House seats after today.

A pickup of three seats in Ohio would give Democrats control of 10 of the state’s 18 seats. The Ohio General Assembly is still controlled by Republicans, but there is a Democrat in the governor’s mansion.

In Michigan, if Democrats were to win the two competitive races, it would give the party control of eight of the state’s 15 seats. Control of the state legislature is split, and control of the governorship is up for grabs in 2010.

In North Carolina — one of the fastest-growing states in the country and all but certain to gain at least one new seat in reapportionment — a pickup of one House seat and Senate seat would move the delegation from tied to the Democratic column. Sen. Elizabeth Dole (R-N.C.) and Rep. Robin Hayes (R-N.C.) are being heavily targeted by Democrats and could go down to defeat today.

With the presidential campaign of Sen. Barack Obama (D-Ill.) paying more attention to the Rocky Mountain West and Southwest, those areas are likely to be a top priority for Democrats in the next round of redistricting.

In Arizona, a pickup of one seat would put Democrats ahead, with five of eight seats. Aside from Renzi’s seat, Rep. John Shadegg (R-Ariz.) is also being targeted as a potential pickup for Democrats.

Meanwhile, New Mexico could go from having a 3-2 GOP majority in the Congressional delegation to being entirely represented in Congress by Democrats. With Sen. Pete Domenici’s (R) retirement, Rep. Tom Udall (D) is favored to win his seat. Democrats also appear poised to win the two open House seats left vacant by Reps. Heather Wilson (R) and Steve Pearce (R), who is facing off against Udall today.

New Mexico Gov. Bill Richardson (D) is term-limited and can’t seek re-election in 2010. Democrats control both the state House and Senate, making next cycle’s gubernatorial race a top priority in terms of the party’s redistricting strategy.

While today’s Congressional results will no doubt be a factor as party strategists look ahead to reapportionment and redistricting in the 2012 cycle, the outcome of the presidential election will also have a big impact.

Campaign strategists who follow the redistricting process closely note that if Obama is victorious today, it will be the first time since 1960 — but more importantly the first time since passage of civil rights rights legislation in the mid-1960s — that a Democratic administration will be in power during a Census and redistricting process. That means a Democratic-appointed attorney general and Justice Department, whose Civil Rights Division is responsible for approving the new legislative maps of 16 states under the Voting Rights Act, will oversee the process.