Democrats begin with a larger base, with the states they won in both of the past two presidential elections accounting for 246 electoral votes. In comparison, the states that Republicans won in both of the most recent elections account for 180 electoral votes. That leaves the nine states Obama took away from the Republicans — Colorado, Florida, Indiana, Iowa, Nevada, New Mexico, North Carolina, Ohio and Virginia.

Those nine states will be the first targets of the Republicans, and already they are putting Indiana in their column. Few Democratic strategists dispute that assessment — Obama won there by a single percentage point in 2008, and the state has reliably voted Republican in presidential elections for decades.

Of the remaining eight, Republicans see their greatest opportunities in two southern states Obama carried: North Carolina and Virginia. Obama advisers have a different view, arguing that the electorates in both states, which include sizable African American populations as well as significant numbers of younger voters and well-educated newcomers, are prime prospects for Obama’s candidacy.

Florida and Ohio, two of the remaining Obama takeaway states, have been the focus of pitched battles in the past three presidential elections. Both could be competitive again. Democrats believe Florida is the less difficult of the two, if only because of the growing non-Cuban Hispanic population and the opportunity to expand the electorate. Economic problems abound there, however, and Republicans made major gains in 2010…

Nevada is ground zero of the home foreclosure crisis and has the nation’s highest unemployment rate. Colorado also will be a challenging environment for Obama, though he has a template for winning based on the strategy employed last year by Sen. Michael F. Bennet (D), who survived in a tough year thanks in part to mistakes by his opponent.