US elections 2010: The basics

Predictions from five leading US political websites suggest that 12 states lie at the heart of the battle for control of the US Senate in the mid-term elections.

Forecast for battleground states

  • D = Democrat
  • R = Republican
  • Toss-up
Current Forecasts
States RCP Sabato Cook NYT Rothenburg Aggregated
Arkansas Former Democratic state steadily swinging into the Republican camp

Democratic two-term Senator Blanche Lincoln is trailing her opponent, Republican Congressman John Boozman, by a wide margin in all pre-election opinion polls. Ms Lincoln is one of the most moderate Democratic senators, but this is no longer enough for a state that is becoming more and more Republican. Though it has a Democratic governor it voted for the Republican candidate in the last three presidential elections. Ms Lincoln is widely expected to lose her Senate seat and two House seats held by Democrats in the last Congress could also become Republican pick-ups.

d r r r r r r
Indiana Popular Democrat's retirement creates opening for Republicans

When long-standing Democrat Evan Bayh announced that he would be retiring at the end of this session, his Indiana senate seat shot to the top of the Republicans' target list. Indiana is a fairly conservative state, and the Republicans appear to have the wind in their sails this year. They have nominated a top-tier candidate - former senator Dan Coats - and are highly favoured to win. Congressman Brad Ellsworth, the Democrats' candidate, is playing up his opponent's lucrative post-senate lobbying career, but for him it's an uphill struggle.

d r r r r r r
North Dakota A safe seat for Republicans as another veteran Democrat retires

The Republicans are almost certain to pick up retiring Democratic senator Byron Dorgan's North Dakota senate seat. Mr Dorgan was first elected to the House of Representatives in 1980 and moved to the Senate in 1992, winning re-election three times. But even he might have struggled to hold on to his seat this year, in what is now a solidly Republican state. The Republicans' chances were boosted even further when they recruited the state's long-serving governor John Hoeven as their candidate to stand against Democrat Tracy Potter, a state senator who has little name-recognition outside his home district.

d r r r r r r
Wisconsin Democratic Senator Russ Feingold may lose, but he's fighting hard

Democratic Wisconsin Senator Russ Feingold is a staunch liberal, famous for spearheading the Senate's efforts to reform campaign finance rules. He also voted against the now hated bank bailout in 2008. He has served as Wisconsin's senator since 1993, but is facing the fight of his career against wealthy industrialist Ron Johnson, the Republican candidate. Johnson has opened up a lead over Feingold in a number of polls, and it looks like the voters in this swing state could swing behind the Republican Party.

d r r r r r r
Colorado Tea Party man has chance in state that's becoming more Democratic

Incumbent Democratic senator Michael Bennet has been in the job since January 2009, when he was appointed to fill the vacancy left by Ken Salazar (picked by President Obama as his Interior Secretary). He faces Republican Ken Buck, a district attorney backed by conservative Tea Party activists. Colorado is becoming increasingly fertile ground for Democrats, due in part to its growing Latino population, but it has a history of libertarian conservatism that could benefit the Republican contender. Mr Bennet will have been hoping that Mr Buck would repeat some of the gaffes he made in the Republican primary (when asked why voters should choose him and not his rival, a woman, he replied "because I don't wear high heels"). But Mr Buck appears to be running a disciplined campaign.

d tossup r tossup tossup tossup tossup
Illinois President Obama's old seat should have been safe for Democrats

Despite the fact that the vacant Senate seat used to belong to President Barack Obama, the Republicans have a decent chance of winning here. Neither the Republicans nor the Democrats have the candidate they would have wished for. The Democratic candidate, state Treasurer Alexi Giannoulias, is tarnished by association with his family's bank, which was seized by federal regulators in April after it collapsed. The Republican candidate, Mark Kirk, is a moderate Congressman with a long track record in Illinois politics, but he has been caught lying about his military service. He was not, as he claimed, named "Intelligence Officer of the Year" during his naval career, nor was he shot at while flying over Iraq or Kosovo. The result is a very close race.

d tossup r tossup tossup tossup tossup
Nevada Republicans would love to oust Democratic Senate leader Harry Reid

The seat is being defended by the top Senate Democrat Majority Leader Harry Reid, whose scalp the Republicans would dearly love to take. Nevada's economy has been badly hit by the financial crisis, and Mr Reid appeared to be in serious trouble, before Sharron Angle, a Tea Party favourite, beat the mainstream candidate Sue Lowden to the Republican nomination. Despite holding some controversial views - she favours abolishing the US Department of Education, withdrawing from the UN, and privatising Medicare and the US pensions system - Ms Angle could still de-throne Mr Reid.

d tossup r tossup tossup tossup tossup
Pennsylvania Key swing state that may swing Republican this year

This race pits Pat Toomey, a Republican ex-congressman backed by fiscal conservatives and Tea Party activists, against Democratic congressman Joe Sestak, who won his party's nomination after a bruising primary against veteran Senator Arlen Specter (following Mr Specter's defection from the Republican to the Democratic Party). The Democratic hierarchy had been convinced that Specter would have a better chance of beating Toomey than Sestak, but Sestak has been creeping up on the Republican in the polls. Pennsylvania is a swing-state, and could well swing the Republicans' way this year, but neither candidate is running away with the race.

d tossup r tossup tossup tossup tossup
Washington If Republicans want a Senate majority, they may have to win here

Incumbent Democratic Senator Patty Murray leads her Republican opponent, Dino Rossi, in most polls, but is by no means unassailable. The Washington senate seat is approximately 10th on the Republicans' list of potential gains - and they need 10 gains to win a majority, so this state could be crucial. But political trends in Washington state have been moving in the Democrats' favour in recent years, so Mr Rossi - who was narrowly defeated in the state's 2004 and 2008 gubernatorial elections - faces an uphill struggle.

d tossup d tossup tossup tossup tossup
West Virginia Popular governor fights for Senate against Republican tide

West Virginia is becoming a Republican stronghold, so when veteran Democratic Senator Robert Byrd died in June, triggering a special election, it was seen as a possible Republican pick-up. The Democrats have the strongest possible candidate in popular state governor Joe Manchin, but Republican candidate John Raese, a local businessman, has pulled level with Manchin in the polls, and could well win.

d tossup d tossup d tossup tossup
California Republican ex-Hewlett Packard CEO may capture liberal stronghold

Despite its liberal reputation, Californian voters do sometimes elect Republicans, as outgoing Governor Arnold Schwarzenegger can testify. In the Senate race, incumbent Democratic senator Barbara Boxer is facing a tough challenge form a high-profile Republican opponent: former Hewlett-Packard CEO Carly Fiorina, who has been able to use her personal wealth to help fund her campaign. The two candidates are virtually neck and neck in the polls, though Senator Boxer's ratings have shown signs of strengthening in recent days. Her chances will be boosted if Democrats turn out in force on election day. Turnout among Democrats tends to be low in mid-term elections, but this time a ballot initiative on the legalisation of marijuana in California may encourage more to go to the polls and cast a vote.

d tossup d tossup d d d
Kentucky Ultra-conservative Republican provides Democrats with slim chance

The Republican candidate is Rand Paul, son of the libertarian 2008 presidential candidate Ron Paul. He won the nomination with the support of the Tea Party, but has been a somewhat gaffe-prone candidate - he defended BP during the gulf oil spill, and questioned the constitutionality of landmark civil rights legislation protecting African-Americans. The Democratic candidate is state Attorney General Jack Conway - a strong choice, but probably not strong enough to win, unless Mr Paul slips up badly on the campaign trail.

r r r tossup r r r
States RCP Sabato Cook NYT Rothenburg Aggregated

The websites are: Real Clear Politics, Sabato's Crystal Ball, The Cook Political Report, the New York Times, and The Rothenberg Political Report.

These are the same sources used for our pundits' forecast of the election result (substituting the New York Times for NYT blogger Nate Silver) - with the addition of RealClearPolitics, because it generates its predictions in a different way, by aggregating polls.

For a Senate seat to make it into our chart, one or more of the websites must give it at least a "toss-up" chance of changing from Democratic to Republican, or vice-versa.

The aggregate score in the right-hand column shows the majority verdict - red for Republican, blue for Democratic or red-and-blue for "toss-up".

It suggests that:

  • Four states currently held by a Democratic senator will be won by a Republican
  • Republicans will hang on to the one seat - in Kentucky - where they face a serious challenge from the Democrats
  • Six Senate seats that are held by the Democrats are toss-ups

Seats Contested (37)

  • Held by Democrats (19): Arkansas, California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Indiana, Maryland, Nevada, New York (X2), North Dakota, Oregon, Pennsylvania, Vermont, Washington, West Virginia, Wisconsin
  • Held by Republicans (18): Alabama, Alaska, Arizona, Florida, Georgia, Idaho, Iowa, Kansas, Kentucky, Louisiana, Missouri, New Hampshire, North Carolina, Ohio, Oklahoma, South Carolina, South Dakota, Utah

The chart does not distinguish between predictions that a state is "safe", "solid", "likely", "leaning", or "favoured" for one party or the other, nor does it distinguish between a state described as a "toss-up" or a "toss-up tilting" to one part or the other. Any state not featured on the chart is at least "leaning" towards the party that currently holds it.

North Dakota is in fact regarded as "safe" or "solid" for the Republicans by all the websites, so is more of a swing state (in this election) than a battleground state.

Updates:

31 October - Real Clear Politics moves California from "Leans Democrat" to toss-up.

29 October - Rothenberg and the New York Times move California from toss-up to "Lean Democrat". This changes the aggregated result for California to Democratic. The New York Times also moves West Virginia from toss-up to "Leans Democrat" and Rothenberg moves Kentucky from toss-up to "Lean Republican".

28 October - Sabato moves Illinois and Nevada from toss-up to "Leans Republican", and Washington and West Virginia from toss-up to "Leans Democratic".

26 October - RealClearPolitics moves Kentucky from toss-up to "Leans Republican" and California from toss-up to "Leans Democrat".

25 October - Rothenberg moves California from "Leans Democrat" to toss-up. The New York Times moves Wisconsin from toss-up to "Leans Republican", California from "Leans Democrat" to toss-up, and Missouri from toss-up to "Leans Republican". As none of the five websites give the Democrats a toss-up chance of winning the Missouri seat, it falls off our table.

21 October - Charlie Cook moves Wisconsin from toss-up to "leans Republican", Missouri from toss-up to "leans Republican", and Connecticut from toss-up to "leans Democratic". As none of the five websites now give the Republicans a toss-up chance of winning the Connecticut seat, it drops out of our table.

20 October - RealClearPolitics moves Pennsylvania from "leans Republican" to toss-up.

19 October - RealClearPolitics moves Kentucky from "leans Republican" to toss-up

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