There are many states that will have ballots chock-filled with exciting and competitive races, but if you are looking for a place where a big GOP political wave might show up early in the evening of Nov. 2 — or for evidence that it won’t be as big as some Republicans hope — you could do worse than focusing on Pennsylvania.

[IMGCAP(1)]Voters in the commonwealth will be choosing a new governor and a new Senator in the fall, but in addition, 10 of the state’s 19 Congressional districts have races worth watching.

Going back at least to the end of World War II, the two major parties have alternated eight-year control of the governorship, so Republicans have reason to be optimistic about their chances of winning that office.

State Attorney General Tom Corbett (R) has been holding a 7- to 10-point lead over Allegheny County Executive Dan Onorato (D), no doubt partially a reflection of Democratic Gov. Ed Rendell’s problems with the state economy and budget.

Both Corbett and Onorato come from Western Pennsylvania — the Republican is a former assistant district attorney in Allegheny County and a former U.S. attorney for the Western District of Pennsylvania — so the geographic voting that often takes place in Pennsylvania won’t be a factor this year.

Corbett, 60, has won two statewide races for attorney general, in 2004 and 2008, and served an additional 15 months in the office in the mid-1990s when then-Gov. Tom Ridge (R) tapped him to fill a vacancy. Onorato, 49, who served on the Pittsburgh City Council before moving into county government, has never run statewide or held statewide office.

Corbett’s victory wouldn’t be a surprise or even an indication of a broader wave, but a strong win by Republican Senate nominee Pat Toomey over Democratic Rep. Joe Sestak could well be a sign of a more significant statewide wave.

Both Toomey and Sestak hail from Southeastern Pennsylvania, and each ran in a Senate primary against Sen. Arlen Specter (D), but their differences are obvious.

Toomey, 48, is a former three-term Congressman and former president of the Club for Growth. A one-time Wall Street trader, he and his brothers opened a restaurant/bar in Allentown. From there, he went into politics, including an unsuccessful 2006 GOP primary challenge to Specter.

Sestak, 58, served in the Navy for more than three decades, achieving the rank of vice admiral. He knocked off a GOP incumbent in 2006 and was easily re-elected two years later. He has been a solid supporter of the Democratic agenda while in Congress.

While polls conflict, Toomey and Sestak generally have been running about even. Toomey usually appears the more poised of the two candidates, and Sestak is likely to be on the defensive over the economy and his voting record. While the race is a tossup, it’s a bit easier to imagine Sestak, who has earned the reputation of being a difficult person to work for, imploding.

A solid Toomey win would be a bad sign for Democrats down the ballot.

Eight of the 10 House seats worth watching are held by Democrats: Reps. Kathy Dahlkemper (3rd district), Jason Altmire (4th district), Patrick Murphy (8th district), Christopher Carney (10th district), Paul Kanjorski (11th district), Mark Critz (12th district), Tim Holden (17th district) and Sestak’s open 7th district. The two seats held by Republicans are Rep. Jim Gerlach’s 6th district and Rep. Charlie Dent’s 15th district.

Of the eight Democratic seats, Sestak’s open seat and veteran Rep. Paul Kanjorski’s now appear to be the best opportunities for Republicans. Former U.S. Attorney Pat Meehan (R), who is running against Democrat Bryan Lentz in the open seat, and Hazleton Mayor Lou Barletta (R) are experienced in the limelight and now benefit from strong poll numbers.

But the other GOP hopefuls probably will need to ride a wave to victory.

Former U.S. Attorney Tom Marino, running against Carney, and state Sen. Dave Argall, who is challenging Holden, didn’t show enough cash in the bank on June 30 to be taken all that seriously — Marino had $11,000, while Argall showed just $29,000.

Both districts went for Sen. John McCain (R-Ariz.) in the 2008 presidential race, however, and both GOP candidates have a base and some reputation. A big wave — a really big wave — could sweep them in.

In Western Pennsylvania, GOP primary upset winner Keith Rothfus starts out as an underdog against Altmire, while Mike Kelly is unproven against Dahlkemper. Both incumbents have considerable financial advantages in areas where fundraising is not always easy, particularly in tough economic times.

In the 12th district, where Critz won a special election, Republicans hope for a reversal of that outcome in November. It certainly isn’t likely, but in a large Republican state wave, the district can’t be ignored.

Finally, Murphy faces a rematch against former Rep. Mike Fitzpatrick. Murphy nipped the Republican in a horrible year for the GOP, 2006, so the changed political environment certainly makes this a race to watch, especially in a wave.

Democrats are mounting stiff challenges to Republicans Gerlach and Dent. The Democratic nominees, Manan Trivedi against Gerlach and John Callahan against Dent, are quality candidates, but a political wave can drown even strong challengers.

Republicans have a slew of challengers in the state — more than in any other state — but many of them haven’t yet put together the kinds of campaigns they’d need to win. If Republicans win four more House seats in Pennsylvania, they are likely to take back the House. With a gain of five, it would be a done deal.

Stuart Rothenberg is editor of the Rothenberg Political Report.