Today effectively marks the end of the primary election season and the true beginning of the general elections. It’s not only one of the last primary days, but one of the biggest including Delaware, District of Columbia, Maryland, New Hampshire, New York, Rhode Island and Wisconsin.

[Ed. note: Jon will be liveblogging results all night. Delaware polls close at 8pm EDT, with a number of others closing at 9. Look for results and reaction here on FDL's Elections page.]

Delaware

Senate – In the Republican primary, establishment-backed and long-time Rep. Mike Castle faces Tea Party insurgent Christine O’Donnell. There are some signs that Castle could suffer the same fate as Sen. Lisa Murkowski (R-AK) for similar reasons. We will see tonight if the Tea Party Express can pull out another primary upset. Castle has a huge fundraising advantage, but O’Donnell has a lot of outside money being spent on her behalf. The latest PPP poll gives O’Donnell a mere three-point lead at 47 percent to Castle’s 44 percent — within the margin of error.

At-Large – The Republican primary is a battle between establishment choice Michele Rollins and Glen Urquhart. They have each raised and spent roughly the same amount as of the last campaign finance filing date, but most of Urquhart’s money comes from a half-million dollar personal loan. Earlier this year, Rollins won the state party’s convention. A recent PPP poll (PDF) of the race has Urquhart leading 50 percent over Rollins at 38 percent.

DC

Mayor – In the weird legal bizzaro world that is the District of Columbia, the office of mayor is the highest elected position, with many of the same responsibilities as a state governor. Given how incredibly Democratic the district is, the primary tonight is the election. The battle is between incumbent Adrian Fenty and council member Vincent Gray. A Washington Post poll found Gray with a huge lead over Fenty, 53 to 36, among likely voters. Fenty draws strong support from white voters, while Gray leads with African Americans. A recent Clarus Research Group poll found Gray leading Fenty, 45 to 38.

Maryland

MD-01 – Maryland’s 1st district is one of the most Republican-leaning districts to be represented by a Democrat, Frank Kratovil. In the Republican primary, it is a fight between Rob Fisher and Andy Harris. Harris is the choice of much of the party’s establishment, has a large fund raising advantage, and will likely win tonight. Fisher is trying to run an “outsider” campaign against Harris.

Massachusetts

MA-09 – Probably the biggest primary race in the state is that of labor organizer MacDonald D’Alessandro versus incumbent Democrat Stephen Lynch. D’Alessandro was SEIU’s New England political director and is challenging Lynch from the left. A key complaint against Lynch was his vote against the new health care law. So far this year, several poorly funded left-leaning challengers with fewer skills in campaigning have won relatively large shares (30-48%) of the vote in primary challenges against incumbent Democrats; few have actually managed to defeat the incumbents, however.

MA-10 – Rep. Bill Delahunt’s retirement has created a competitive primary for both parties. On the Democratic side, it is a fight between Bill Keating and Rob O’Leary. Keating is the better funded of the two candidates, but O’Leary has recently benefited from the endorsement of the Boston Globe. On the Republican side, it’s a fight between Jeff Perry and Joe Malone. Perry has been endorsed by the NRA.

New Hampshire

Senate – Republican Attorney General Kelly Ayotte is the establishment choice to replace retiring Senator Judd Gregg. She is running against Ovide Lamontagne, Bill Binnie and Jim Bender. The latest Magellan poll found Ayotte at 34 percent, Lamontagne 31 percent, Binnie 14 percent and Bender at 10 percent. The most recent PPP poll has it Ayotte 37 percent, Lamontagne 30 percent, Binnie 13 percent, Bender 12 percent. While Lamontagne has raised the least money of the four, he has benefited from the important endorsement from the New Hampshire Union Leader. Not too be out done, Ayotte has been endorsed by conservative standard-bearers Sarah Palin and Sen. Tom Coburn. It looks like Ayotte will win, but that is partly because a divided field is splitting the hardcore conservative vote.

NH-01 – Four well-financed Republicans — Sean Mahoney, Frank Guinta, Richard Ashooh and Robert Bestanii — are all vying for the right to challenge incumbent Carol Shea-Porter. Sean Mahoney is the best funded of the Republicans and leads according to the only recent poll I can find, by Americans for Prosperity. The poll has Mahoney leading the field at 32.6 percent, with Guinta at 25.9 percent, Ashooh at 9.9 percent and  Bestani lagging with 5.1 percent of the prospective vote.

NH-02 – Both parties have competitive primaries for this open seat. On the Democratic side, it is Ann McLane Kuster versus Katrina Swett. Swett is effectively the “Queen of the Liebercrats” and would likely become an official Blue Dog. She co-chaired Joe Lieberman’s 2004 presidential campaign, and supported Lieberman in his 2006 independent bid. Kuster, however, holds a significant fundraising advantage.

On the Republican side. former Rep. Charles Bass is trying to win back his seat. He must first defeat radio host Jennifer Horn and pilot Bob Giuda, who are also competing for the nomination.

New York

Governor – The Republican primary is between former Rep. Rick Lazio and self-funded millionaire Carl Paladino. A Quinnipiac poll from earlier this month showed Lazio ahead, 47 percent to 35 percent. Both candidates trail Democrat Andrew Cuomo by a wide margin. A Siena poll released Saturday showed the primary tightening, now neck-and-neck with Lazio at 43 percent to Paladino’s 42 percent (PDF).

NY-01 – Incumbent Dem Tim Bishop is thought to be vulnerable this year, and, as a result, three Republicans — Randy Altschuler, Christopher Cox and George Demos — are tearing each other apart for the right to challenge him this November. The race has been bitter and extremely expensive. Cox has spent a million dollars of his own money on the race; not to be outdone, Altschuler has spent two million dollars.

NY-13 – In the all-Michael district, we have Michael Grimm (who has the support of Sarah Palin) and Michael Allegretti (who is endorsed by the previous Representative from the district, the scandal-tainted Vito Fosella, Jr.) competing in the Republican primary to take on incumbent Democrat Michael McMahon.

NY-14 – Incumbent Democrat Carolyn Maloney has managed to incur the wrath of Wall Street with votes on credit card and financial reform. She is being challenged by Reshma Saujani whose resume includes work for three different hedge funds. Saujani’s list of donors looks like a who’s who of Wall Street millionaires. Saujani is the ultimate anti-populist, pro-banker challenger in what has been an otherwise very anti-Wall Street election cycle. Maloney was recently endorsed  by the New York Times.

NY-15 – Despite being involved in several mini-scandals that would probably have sunk most other politicians’ careers, Charlie Rangel looks like he will survive the primary tonight due to a lack of a single stand-out opponent, a huge fundraising advantage, and a very long history in the district. He is being challenged by former Rangel aide Vince Morgan, union organizer Jonathan Tasini, and NYC government hand Joyce Johnson. It is worth keeping an eye on this race to see how loyal to or fed up with Rangel the voters of the district may be. Johnson has the endorsement of the New York Times.

NY-23 – After losing the special election, Doug Hoffman is really determined to challenge Democrat Bill Owens again. Hoffman is competing against millionaire Matt Doheny for the Republican nomination. Doheny has the support of most of the party establishment and has already dropped a million dollars out of his own pocket into the race. Even if Hoffman loses the Republican primary — which seems likely — he remains committed to running in the general on the Conservative Party ticket. It looks like Owens might just have a chance of keeping the district, thanks again to Hoffman splitting the conservative vote.

Rhode Island

RI-01 – There is a heated four-way Democratic primary between David Cicilline, Anthony Gemma, William Lynch and David Segal to replace Rep. Patrick Kennedy. Cicilline has a large fundraising advantage and strong name recognition as a result of being mayor of Providence. Segal has tried to stand out by claiming to be the true progressive in the field. A poll from early August shows Cicilline leading the field at 32 percent, with Lynch at 15 percent, Gemma at 11 percent, and Segal at 5 percent of voters polled. Given that the poll’s sample size was a mere 174 voters, I would take these results with a big grain of salt.

Wisconsin

Governor – Scott Walker and Mark Neumann are competing for the GOP gubernatorial nomination. Walker is the perceived frontrunner in the primary.

WI-07 – Best known for his role on MTV’s reality television program “The Real World,” Sean Duffy is running against Dan Mielke. Duffy holds a strong fund raising advantage, has the backing of the national party which declared him one of their “young guns,” along with fund raising help from Sarah Palin.

WI-08 – The Republican primary is a three-way race between Reid Ribble, Roger Roth and Terri McCormick. The winner will take on incumbent Dem Steve Kagen in the general.