Beau Biden, Delaware's attorney general and the son of Vice President Joe Biden, is increasingly assumed to be the Democratic nominee for Joe Biden's vacated Senate seat. Republican Michael Castle, who represents Delaware in the House of Representatives, has announced he will run in the 2010 election. It won't be easy for either candidate: A poll out Thursday shows the two evenly matched. Should Biden run -- a campaign that would coincide with a slew of 2010 congressional races that are seen as a collective referendum on his father's White House -- he would no doubt gain significant national attention. Here are the smart early reads on the race.

• Castle a Formidable Foe  David Weigel recounts Rep. Michael Castle's strong electoral history. "Castle has been winning elections in the state since Lyndon Johnson was president, and he won his 9th term last year with 61 percent of the vote," Weigel writes at the Washington Independent. "Castle has a statistically insignificant 46-45 lead, bolstered by an 8-point lead among independents and the support of 21 percent of Democrats. Results like this probably make a Biden run more likely," Weigel says. "President Obama's popularity in the state is still sky-high."

• Americans Love Royalty  Markous Moulitsas explains why Biden performs better in the poll than any other Democrat. "Castle easily leads other potential match ups (Castle 51 Kaufman 37, Castle 49, Carney 41, Castle 51 Coons 39), but the Biden-Castle one is most likely because the political establishment loves its monarchies, and so do the voters," writes Moulitsas, who heads influential liberal opinion site Daily Kos. "Both Castle and Biden have nearly identical approval ratings as well, providing perhaps the most even matchup of the cycle. While some prognosticators are already slotting this race as a 'lean Republican', the data suggests this is about as pure a 'toss-up' as you can have in politics."

• It's All About Democrats  Taegen Goddard points out Biden's relatively middling performance among Democrats. "Key findings: While Castle has solid Republican support (82% to 9%), Biden gets less than three-quarters of Democrats (72% to 21%). Independents lean toward Castle (48% to 40%). If Biden brings Democrats home, it gets much harder for Castle to win."

• It's All About Young Vs Old Voters  Congressional Quarterly's Greg Giroux notes the split in voters by age group. "Biden, 40, has his highest approval rating (71 percent) among voters age 18 to 29, while Castle, 70, get his strongest mark (68 percent) among voters 60 and over," he writes. Older voters, of course, are more likely to turn out than young voters. "CQ Politics currently rates the race Leans Republican."

• Castle Must Demonstrate Centrism  Matthew Yglesias thinks Castle has a shot if he can distance himself from the GOP. "Castle is super-popular in Delaware and stands a good chance of winning. But obviously the Republican leadership as a whole is very much not popular in Delaware. Will Castle be able to persuade people that he won’t just be a lockstep obstructionist? If he wins, will he deliver on that promise and build a more robust moderate wing of his party’s caucus? Or will his popularity melt away in the cold light of a campaign?"
  

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