Washington ? With the return this week of the 109th Congress after last year’s bruising session, it is open season for speculation about November’s midterm election. The collapse of President Bush’s landmark Social Security initiative, the battles over Supreme Court nominations, the scandals real and threatened involving Republican leaders, and the signs of fraying inside the GOP coalition have raised the stakes in the coming House and Senate campaigns.

While Democrats remain underdogs to capture control of either chamber, the exceptional unity they have displayed on a variety of domestic and economic issues has bolstered their hopes for gains.

It’s guaranteed that banner Senate races, such as the Pennsylvania contest between Republican incumbent Rick Santorum and Democratic state Treasurer Robert Casey Jr. will grab a large share of the headlines.

But, at the risk of being contrarian, let me suggest that the most significant results of 2006 will not involve the Senate or House but instead will be found in six Midwest governors’ races.

The campaigns in Illinois, Iowa, Michigan, Minnesota, Ohio and Wisconsin will tell us more about the direction of the country and the shape of the 2008 presidential battleground than any of the battles for Capitol Hill – where incumbency advantages in both money and gerrymandering are likely to skew the results.

Governors are closer to their constituents than most senators or representatives, and they exert more influence on presidential politics than their federal counterparts, in part because the nominees themselves most often come from the statehouses.

Republicans are likely to consolidate their current strength among governors across the South from Florida through Texas. Democrats are poised to solidify their grip on the state capitols in the Northeast, with strong candidates available to challenge in New York and Massachusetts, where Republican incumbents are retiring.

But the Midwest is a real battleground, with one open seat in each party and three Democrats and a Republican facing tough re-election battles.

No state is more up in the air than Ohio, the crucial battleground in the 2004 presidential race. Retiring Republican Gov. Bob Taft rated in one end-of-the-year survey as the least popular incumbent in the country, with a 17 percent job approval. Rep. Ted Strickland now has an open path to the Democratic nomination, while Republicans face a possible primary battle among three statewide officials, Secretary of State Ken Blackwell, Atty. Gen. Jim Petro and State Auditor Betty Montgomery.

In Iowa, the other open seat, where Democratic incumbent Tom Vilsack is retiring voluntarily, the Republican front-runner is Rep. Jim Nussle, the chairman of the House Budget Committee, who is opposed by businessman Bob Vander Plaats. Secretary of State Chet Culver, son of former Sen. John Culver, heads a Democratic field that also includes a Vilsack protege, former state Economic Development Director Mike Blouin.

In Minnesota, Republican Gov. Tim Pawlenty has battled the opposition Legislature over budgets and other issues but was credited with a 59 percent approval score. Atty. Gen. Mike Hatch, state Sens. Becky Lourey and Steve Kelley and developer Kelly Doran are seeking the Democratic-Farmer-Labor endorsement.

In Wisconsin, Democratic Gov. Jim Doyle has faced the mirror-image of that problem, squabbling regularly with Republicans in the Legislature. Doyle has a 48 percent job approval and two credible Republican challengers, Rep. Mark Green and Milwaukee County Executive Scott Walker.

In Michigan, Democratic Gov. Jennifer Granholm is personally popular but her state’s continuing economic woes have left her with a shaky 41 percent job approval. The Republican challenger is likely to be Dick DeVos, the former head of the Alticor (Amway) sales network.

And finally in Illinois, Democratic Gov. Rod Blagojevich has accumulated a huge campaign war chest but also a slew of investigations and controversies as he bids for a second term. The weakened Republican establishment has rallied behind state Treasurer Judy Baar Topinka, but she has opposition from state Sen. Bill Brady, securities executive Jim Oberweis and Ron Gidwitz, a businessman-philanthropist.

In the last presidential race, Ohio and Iowa went narrowly to Bush; Michigan, Minnesota and Wisconsin barely held for John Kerry. Illinois was the only one of the six states that delivered a solid Democratic majority.

Those states figure to be just as important in 2008, which means that what happens there this year will be well worth watching.