After spending the week focused on races for the U.S. House, it's time to take another spin around the various Senate races that will determine if Democrats hang on to power in that chamber or not next Tuesday.

For now, the conventional wisdom in Washington, D.C. is pretty much the same in both parties about the Senate.  Republicans will pick up seats, but not get the ten seats they need to take over the chamber.

"I think we're going to get close in the Senate," said former GOP national party chief Ed Gillespie, who predicts Republicans will pick up either "7 or 8 seats" on Tuesday night.

"We're going to win West Virginia and Connecticut," says former Democratic party chief Terry McAuliffe, "which virtually makes it almost impossible for the Democrats to gain control."

McAuliffe is right on one point, that Republicans don't have much wiggle room on Election Night.  But let's go state-by-state to see what happens.

First, let's assume that Republicans hold onto Senate seats in New Hampshire, Florida, Kentucky, Missouri and Ohio.  The polls have gotten a bit tighter in Florida, but Marco Rubio still seems to be the favorite.

As of now, the GOP is definitely favored to win Democratic Senate seats in Arkansas, Indiana and North Dakota.

Now let's get to the next tier of seats:

WISCONSIN - Sen. Russ Feingold (D-WI) is trying to fight back, but he doesn't seem to be getting traction against political rookie Ron Johnson (R), who leads by an average of 6 points in the polls.  This could be a tough state for Democrats on election night.

PENNSYLVANIA - Last week, polls indicated this race had closed, with momentum for Rep. Joe Sestak (D-PA).  But this week, the momentum is all with Republicans, as Pat Toomey (R) has been up as much as 8 points in a daily tracking poll.  Like in Wisconsin, Republicans are threatening to win big in both the Senate and Governor's races.

ILLINOIS - This race has been slowing sliding towards the Republicans, as has the Governor's race.  Neither candidate has excited the voters, but it would be a big, symbolic win for the GOP to grab the Senate seat once held by Barack Obama.

If the Republicans win those three, then they are at plus-6 for the Senate.  The road to plus-10 is difficult.  Republicans need to win four of the next five seats.

NEVADA - The numbers seem to have been moving more and more towards Sharron Angle in recent days, but no one seems to know what to expect out of this on Election Day.  It obviously would be a big deal to knock off the Senate Majority Leader.

COLORADO - Another race that has been very close, but Tea Party Republican Ken Buck has a slight lead in the poll averages over Sen. Michael Bennet (D-CO).  Republicans have a chance at a couple of House seats in Colorado, so winning this Senate race is a distinct possibility for the GOP.

WEST VIRGINIA - Have the polls really moved hard in favor of Gov. Joe Manchin?  Well, he has done just about everything possible to set himself apart from Democratic leaders and the White House in the last few weeks.  If Republicans can't win this race, then it's almost impossible to take back the Senate.

WASHINGTON - The polls have been back and forth on this one in recent weeks, with short leads for both Sen. Patty Murray (D-WA) and Republican challenger Dino Rossi.  Early voter turnout so far is heavier than two years ago in Democratic King County, which could be a good sign for Murray.

CALIFORNIA - Sen. Barbara Boxer (D-CA) has held short leads here for weeks, as Republican Carly Fiorina has been unable to catch her in the polls.  Will that change?  Right now it's hard to see Boxer collapsing, especially if Jerry Brown is really running away with the California Governor's race.

So, can the GOP win Nevada, Colorado, West Virginia and Washington State?  That's about their best route to a ten seat gain and control of the U.S. Senate.

Nine wouldn't be that bad, though - because it would mean a 50/50 Senate and maybe bring the name "Joe Lieberman" back into play.

Now that would be ironic to say the least.

Four days to go.