Those of us who have been working in and around politics in Washington for the past two decades have been deeply immersed in the machinations of five presidential elections — but until the last one, none of our actual votes were really up for grabs. From 1992 to 2004, both major parties essentially bypassed the D.C. metropolitan area because the outcomes were foreordained: The Democratic nominee would rack up at least six out of every seven votes in the District and carry Maryland by at least a dozen points, while Virginia remained a bedrock of the Republican base as it had been since the LBJ landslide.

The situation changed dramatically in the last campaign, when a surge of new and mostly Democratic African-American, Latino and Asian arrivals in the D.C. suburbs made Virginia into a genuine swing state. After sewing up the nomination in June, Barack Obama chose Bristol for his first rally. He returned to Manassas on the final night of his campaign. And in between, Washington radio and TV stations hardly had room for all the Obama and John McCain ads — the sort of hard-hitting, every-vote-counts spots that only get played in the electoral bellwethers.

Given the winner-take-all nature of the Electoral College and the increasingly precise way voters can be targeted, it’s little wonder that almost all of the candidates’ attention goes to the states either could win — and that the roster of those states for 2012 is already well-defined. Virginia’s on it again, along with just 11 other states. Winning the bulk of their 151 electoral votes means winning the White House.

Both parties are already looking for an edge in each place. Of course, the principal debate everywhere will be on the proposition that the economy’s on the right track and the president deserves the credit. But in the tossups, other policy divides will have particular resonance and could take on outsized importance.

This CQ Roll Call Outlook offers an early campaign season primer on six of the biggest: the road and mass transit needs of the Colorado suburbs, how health care is playing in retiree-rich Florida, ethanol’s likely last stand as a top issue in Iowa, the promise of current trade policy to Michigan’s automakers, EPA regulation of the Pennsylvania natural gas boom and the way the coming defense cuts could change the economy of Virginia.

When those ads come on the radio next fall, the savvy listeners ought to be prepared to decode them.