(NEWSER) - Now that Arlen Specter is flying the Democratic colors, his new party can expect a tangible—if modest—change in his voting behavior, writes Nate Silver of FiveThirtyEight.com. "Democrats have ample reason to be pleased," writes Silver, who crunched the numbers of all previous congressional party-switchers. "Nevertheless, odds are that Specter will line up squarely in the conservative half of the Democratic caucus and will probably leave room to his left for a primary challenge." More»