Republicans definitely dodged a bullet in Illinois' 2006 congressional races. While losing an unofficial 28 seats in the U.S. House and control of that chamber, they lost none in Illinois.

Despite being a blue state which John Kerry carried in 2004 by 545,604 votes and 54.8 percent of the total cast, the Democrats hold only a 10-9 majority in Illinois' congressional delegation. That didn't change in 2006, despite intense Democratic efforts to win Henry Hyde's open 6th District seat, in western Cook County and DuPage County, and against incumbent Mark Kirk in the upscale North Shore 10th District.

Republican Peter Roskam beat the much-hyped Democrat Tammy Duckworth, a wounded Iraq War veteran, by 4,763 votes (getting 51.3 percent of the vote), in a race where each spent more than $2 million. And Kirk, a three-term moderate who was blistered as being a "Bush Republican" and an Iraq War supporter, beat Democrat Dan Seal by 13,621 votes (with 53.4 percent of the vote).

Republicans suffered a major disappointment in the 8th District, which includes parts of far northwest Cook County, western Lake County and McHenry County. But the bad news may presage good news in 2008: Incumbent Democrat Melissa Bean won by 12,726 votes, getting 50.9 percent of the vote, in a three-candidate race. She clearly has not entrenched herself.

In assessing the 2006 congressional results, five "rules" apply in addressing present and future vulnerability:

First is the "25,000-Vote Rule." Any incumbent who wins by a margin of fewer than 25,000 votes is deemed vulnerable at the next election. And any incumbent whose margin declines by 25,000 or more votes, but still exceeds 25,000, should be concerned. Kirk's margin declined from 51,154 votes in 2004 to 13,621 in 2006. Republican Jerry Weller (R-11), whose district stretches from Will and Kankakee counties on the Indiana border west through Grundy, LaSalle and Bureau counties, saw his margin drop from 51,154 votes to 20,196 votes. Even outgoing U.S. House Speaker Dennis Hastert (R-14) saw his margin drop from 94,026 to 37,320.

Second is the "Open-Seat Underperforming Rule." When an incumbent retires, the ensuing contest is always much closer. Hyde won in 2004 by 29,157 votes (with 57 percent of the vote), down from his 2002 margin of 52,476 (65 percent). Hyde's popularity was waning, and the area was changing, but the tightness of the 2006 race does not necessarily mean Roskam will be vulnerable in 2008.

Third is the "Presidential Drag Rule." When a president's popularity falls below 50 percent, his party invariably suffers in mid-term congressional races. That was the case in 2006. Republicans underperformed below their 2004 level by at least 10 percent, due to George Bush.

Fourth is the "Total Aberration Rule." Occasionally scandal turns out an entrenched incumbent. It happened in 1994, when Mike Flanagan upset Democrat Dan Rostenkowski. Some thought it might occur in 2006, jeopardizing Hastert, who caught some blame for the Mark Foley/congressional page situation. It didn't.

Some one who was elected in an aberration, such as Flanagan, is turned out after a term.

And the fifth is the "Wake-Up Call Rule." Veteran Republican Phil Crane saw his margin decline from 51,141 votes and 61 percent of the total in 2000 to 24,649 votes and 57 percent in 2002. That should have rocked Crane out of his indolent lethargy and rocketed him back to Illinois to spend every waking moment in his district. It didn't, and Bean defeated him by 9,191 votes in 2004. The 2006 results are clearly a wake-up call for Kirk, Weller and Hastert.

Here's a look at specific contests:

10th District (Cook County's North Shore, eastern Lake County): Kirk, age 47, is viewed as a natural fit for the district, namely, fiscally conservative but socially moderate and supporting abortion rights, gay rights and gun control. But he's also a U.S. Naval Reserve officer and a supporter of Bush Administration policies in Iraq.

After having won by 70,311 votes, with 69 percent of the votes cast, in 2002 and by 78,275 (64 percent) in 2004, Kirk looked impregnable. He is strong on constituent service and is regularly in the district. His precipitous 2006 plunge is attributable to one issue: Iraq. The liberals and independents who backed Kirk in the past and who are disillusioned with Iraq defected to the unknown Seals.

The Kirk-Seals race was a replay of the bitter 2000 contest between Kirk and liberal Democrat Lauren Beth Gash. Kirk won that race by 5,658 votes, with 51.2 percent of the total cast. Kirk took the Cook County portion of the district by 54-46 percent, and Gash won Lake County 51-49. The 2001 remap made the district more Republican, eliminating Zion and replacing it with half of Palatine Township.

This time Kirk won the 340 Cook County precincts (which include New Trier, Northfield, Wheeling and Palatine townships) 63,058-50,855, with 55.4 percent of the vote; he barely won the 221 Lake County precincts (which stretch from Deerfield and Buffalo Grove north through Lake Forest to Zion) 44,243-42,825 (50.8 percent).

If U.S. troops are still in Iraq in 2008, Kirk has a critical choice: switch or lose. Seals, an investment banker, will run again. Unless Kirk publicly comes out against current Iraq policies, he will be beaten in 2008.

6th District (north DuPage County and parts of northwest Cook County, including Des Plaines, Park Ridge and Rosemont): The much-vaunted DuPage County Republican machine is barely alive, and not very well. But they did their job, and Roskam succeeds Hyde.

Duckworth was recruited by Rahm Emanuel, lionized by the news media and endorsed by major newspapers, became a veritable celebrity, spent almost $3 million -- and still lost. The simple reason: She didn't have a ground game.

Unlike the haughty North Shore, where precinct workers are viewed with disdain, the western suburbs are still fertile territory for door-to-door retail politics. In Cook County's 123 precincts, where the Republicans have no precinct apparatus, Duckworth won 18,468-16,485, with 52.9 percent of the vote. In eastern DuPage County, with a large Hispanic population around Addison, Itasca and Bensenville, Duckworth ran exceedingly well. But Roskam ran up solid margins in Wheaton, Winfield, Carol Stream, Roselle, Glendale Heights, Lombard and Villa Park, due to intensive precinct work. Overall, in DuPage County's 399 precincts, Roskam won 74,638-67,893, getting 52.3 percent of the vote.

Duckworth is being urged to try again in 2008, replicating the Bean strategy. But Roskam is not Crane, and he will relentlessly campaign for the next 2 years. And 2008 will not be as abysmal as 2006 for Republicans. Roskam will never exceed 60 percent of the vote, but if he doesn't get lazy and complacent, he'll be around for a decade or more.

8th District (western Lake County, McHenry County, and Palatine, Schaumburg and Hoffman Estates in Cook County): Bean, age 44, proved that while she's no aberration, but it will be a long time before she's an institution. Despite the advantages of incumbency, a nonliberal voting record, name recognition accrued from her 2002 and 2004 bids, perpetual campaigning, the expenditure of at least $3 million, and a Republican foe who was easily isolated as an "extremist," Bean actually saw her share of the vote decline from 51.7 percent to 50.9 percent.

Bean's vote margin crept from 9,191 to 12,726. She beat Republican David McSweeney 92,046-79,320, with 9,169 votes (5 percent) going to Moderate Party candidate Bill Scheurer, who ran on a get-out-of-Iraq platform. Both Bean and McSweeney backed Bush's Iraq policies. In 2004 Bean won 139,792-130,601, but that was a year with a presidential race, with a higher turnout. In 2002 she lost by 95,275-70,626. So her vote this year, though 47,746 lower than in 2004, was 21,420 higher than in 2002.

On the upside, Bean will have plenty of time to shift her stance on Iraq, perhaps from benchmarks to timetables to a date certain for withdrawal. If she does, Scheurer won't run. On the downside, however, Republicans will have a year to find a more palatable opponent -- which means a moderate, rich, self-funding woman. McSweeney surely will try again, but he's proven himself less popular than Crane.

The 2006 results are telling: In 2004 Crane won the 79 McHenry County precincts by 1,220 votes while McSweeney lost them by 125 votes. Crane lost the 265 Lake County precincts by 874 votes while McSweeney lost them by 4,679, and Crane lost the 175 Cook County precincts by 9,537 votes while McSweeney lost them by 7,922. And Cook County, especially the area around Barrington, was supposed to be McSweeney's base.

Even accounting for the 10 percent anti-Bush underperforming factor, McSweeney clearly was a nonelectable candidate. In Bean's two races against Crane, she crafted the contest as a referendum on an inept and inaccessible incumbent. In 2006 Bean made the race a choice between an "independent-minded" incumbent and an "extremist" challenger.

The Republicans' dream candidate is state Senator Pam Althoff (R-32), a former McHenry mayor and city clerk. They need somebody who can win McHenry County by 4,000 votes and Cook County by 1,000 votes. But she's not a self-funder, as was McSweeney, who spent more $3 million of his own money.

If and when Bean gets an attack-proof Republican foe who can focus all attention and negativity on her record, she will lose. The district is just too Republican. But it may not happen in 2008.