Before Tuesday's election ended, campaigns for the next one were well underway.

The next statewide balloting doesn't take place until 2010, but it won't be many weeks before its campaigns, long germinating below the surface, blossom into view.

The office that Gov. Ed Rendell will vacate has generated the most early interest. But Sen. Arlen Specter's plans to run for a sixth term could also produce some intriguing plot lines. Among them is a potential Democratic battle between a television star and one of the rising stars of the Legislature. A renewed battle for control of the state Legislature adds to the prospects for an intense, expensive political year.

On Friday, Mr. Rendell's spokesman repeated the governor's earlier vow to remain in Harrisburg for the balance of his term.

The state Constitution bars Mr. Rendell from seeking a third term, and Pennsylvania political history has produced a less formal term limit. For more than half a century the Democratic and Republican parties have alternated in control of the governor's mansion in regular eight-year cycles. That would seem a good omen for the GOP as it contemplates a post-Rendell Pennsylvania.

Democrats don't seem deterred by that pattern. Already, on both sides, big fields of potential candidates are weighing the prospects of a bid for the state's top job. One reason why neither side is counting on the precedent of eight-year changeover cycle is that the state's political terrain has shifted in potentially significant ways since Mr. Rendell succeeded former Gov. Tom Ridge.

A state that gave President-elect Barack Obama the largest majority of any presidential candidate since Richard Nixon in 1972 has seen a dramatic increase in Democratic strength and registration. One of the key questions that will be answered in the 2010 contests is whether the Democratic resurgence will sustain itself without the amply financed, labor-intensive nurturing that characterized the Obama campaign's efforts here over the last year.

The would-be candidates will be eyeing one another while trying to line up supporters and contributors at next month's Pennsylvania Society weekend in New York City -- that singular ritual where the floating hierarchies of each party leave the state every year to discuss how to govern it.

On the Democratic side, at least five significant figures, including two from Allegheny County, are considering the governor's race, and there is time for others to emerge -- although, given the formidable logistical challenge of a statewide campaign, not much time.

On the GOP side, two prosecutors, Attorney General Tom Corbett and former Philadelphia U.S. Attorney Patrick Meehan lead the list of potential nominees. Mr. Meehan earned headlines for his office's high-profile investigation of state Sen. Vince Fumo, D-Phila. He has broad ties within the state GOP as a former top aide to Sen. Arlen Specter. He was also a chief strategist for former Sen. Rick Santorum in his first election over Sen. Harris Wofford in 1994.

Mr. Corbett's relatively comfortable victory in a tough year for Republicans was the GOP's only statewide solace Tuesday. He has attracted attention with his investigation into the use of public funds to pay legislative staffers for campaigning. He demonstrated one of the dividends of incumbency last Wednesday as his post-election comments on the ongoing investigation drew headlines throughout the state.

At this point, those two lawyers appear to be on a tier of their own in speculation about the GOP race, but among the other names discussed as potential nominees is Pat Toomey, the head of the conservative Club for Growth, who narrowly missed wresting the Republican Senate nomination from Mr. Specter four years ago.

Allegheny County Executive Dan Onorato and state Auditor General Jack Wagner, former colleagues and political opponents, are among the Democrats' more prominent potential candidates. Mr. Onorato has cultivated connections and fund-raising ties to Democrats across the state. Mr. Wagner's prospects were enhanced by his big re-election victory on Tuesday, where he piled up the largest vote total in the state of any candidate since Sen. Bob Casey's 2004 election as state treasurer.

But if the two former Pittsburgh council members did both get into the race, the state's political world would be watching to see which one would blink first. Sharing the same geographic base, each could make the other vulnerable to competition from contenders from elsewhere in the state.

And it looks like there will be plenty. Others actively considering the race include Lehigh County Executive Don Cunningham, and two wealthy former businessmen, Tom Knox, of Philadelphia, and state Revenue Secretary Tom Wolf.

Despite spending millions of his own money, Mr. Knox, a former finance and health care businessman, lost last year's Democratic primary for mayor of Philadelphia to the eventual winner, Michael Nutter. Before joining the Rendell Cabinet, Mr. Wolf, who has a Ph.D. in political science from MIT, owned a large building supply business based in York County. While a relative unknown politically, he, like Mr. Knox, would be an instantly credible candidate because his wealth would allow him to finance his own race. His York heritage would make him the only candidate from the center of the state.

Mr. Cunningham, a former Bethlehem mayor, also served in the Rendell Cabinet, in the governor's first term. He is more liberal on social issues than the two Allegheny County officeholders. His perch on the periphery of the Philadelphia media market gives him a base in the region that Tuesday's results confirmed as the increasingly dominant source of Democratic votes in the state. But, as with the two Allegheny County officials, if he and Philadelphia's Mr. Knox were both to stay in the race, they would face the risk of fratricide.

Mr. Specter, the state's longest-serving senator, faces potential Democratic challenges from two very different candidates. Rep. Josh Shapiro, 35, a Montgomery County lawmaker whose Harrisburg influence belies his relative youth, is poised to enter the race. Mr. Shapiro was one of the key strategists behind the startling maneuvers that preserved his party's control of the state House two years ago. His base in the Philadelphia suburbs has grown in strength in Democratic politics throughout the last decade.

Chris Matthews, the cable television host, has also been widely mentioned as a Senate hopeful. He has made little secret of his interest in the Senate, in at least a theoretical way, but has never described himself, on the record, as an actual candidate. The former aide of the late House Speaker Thomas P. O'Neill has political roots in the state. His brother, James Matthews, is a Montgomery County commissioner, and was Lynn Swann's lieutenant governor runningmate in 2006.

Mr. Specter has already announced his plans to run for re-election, after twice rebounding from bouts with cancer. Despite his hair's-breadth victory in the 2004 GOP primary, no Republican has yet emerged as a challenger for the GOP nomination. It would be surprising if he remained unopposed within his party, however, as his relatively moderate views on social issues are anathema to many members of his party's conservative wing.

Mr. Specter remains a vigorous campaigner and fund-raiser. His seniority in Washington has allowed him to accumulate a long list of political chits with individuals and communities throughout the state. While he has a track record as a formidable general election candidate, the 2004 results demonstrated his potential vulnerability in a GOP primary. That vulnerability could be compounded by the fact that many moderate Republicans were numbered among the Democratic registration gains over the last year, suggesting that the GOP primary electorate would be marginally more conservative this time around.

Pennsylvania Democrats improved their state House margin to 104-99 from the even slimmer one-vote control they had maintained for the last two years. The stakes for the GOP effort to reverse that in two years will be high as the Legislature elected then will be in charge of the redistricting of a congressional delegation certain to shrink once again after the 2010 Census.