With House Republicans measuring the proverbial curtains in Speaker Nancy Pelosi's office, the focus has turned to whether or not the balance of power could also flip in the Senate.

Certainly momentum and enthusiasm, for now, appears to be on the GOP side, as often happens in the midterms with the party not occupying the Oval Office (how often do we hear that midterms are a ''referendum on the president"?), but most political oddsmakers would caution Minority Leader Mitch McConnell, R-Ky., not to drag out his measuring tape just yet.

Indeed, even McConnell, a student of political history, has said numerous times that he does not expect such a change, though most, McConnell included, do think the chamber will come much closer to the 50-50 split from just a decade ago.

Top political analyst, Charlie Cook of the Cook Political Report, recently said, "It probably won't happen this year," rather that the next two cycles, with Democrats defending twice the number of seats as Republicans, are more likely to result in a GOP majority.

Republicans, according to Cook, need to snag 10 seats held by Democrats, and a look at the slate for this year does indicate that this is not outside the realm of possibility, though at this point Larry Sabato, campaign expert and director of UVA's Center for Politics, agrees with Cook and predicts that the GOP are more likely to pick up just seven seats, not an insignificant number.

Let's first look at those possible flips for Republicans.

Democrats seem most likely to lose the seat held by retiring Sen. Byron Dorgan of North Dakota, and the odds are not in their favor for keeping either Indiana or Delaware, despite Democrats fielding solid competitors in both states.  It's just not a good year to be a Democrat, even if you aren't an incumbent.

The strong anti-Washington mood of the country, as well as the remaining agenda in the Senate tends to favor Republicans.

Democratic leaders will somehow have to deal with a staggering number of expiring tax cuts, and whether or not they choose to take difficult votes ahead of the fall elections (not so likely, according to senior Democratic aides) or punt to a lame duck session, Republicans are poised to pounce.  One senior Senate GOP leadership aide told Fox, “If I were them, I’d wait, but either way, we’re going to say ‘Democrats are going to raise your taxes.’ It’s a total win-win for us.”

Looking at some of the tossup races (it’s worth noting that two-thirds of them belong to Democrats), like Pennsylvania, Illinois, Arkansas, Colorado, and Washington, it’s easy to see how the tax issue will likely figure prominently, particularly in the Keystone State.

Former Cong. Pat Toomey, R-Penn., a staunch fiscal hawk and former head of the anti-tax Club for Growth, is riding high on his fiscal message, even forcing a party switch for former Republican-turned-Democrat Sen. Arlen Specter who was promptly ousted by Cong. Joe Sestak, D-Penn., in the primary. For now, Sestak is holding his own against Toomey in most polls, with an average of polls by Real Clear Politics putting Toomey slightly ahead.

Democrats are also going to have to navigate the treacherous appropriations waters, as they try to wrap up business by November.  They will either have to pass all of their annual spending bills, a highly unlikely prospect, or they will have to get what they can done and go for a short term stopgap spending measure to keep the government running until a lame duck session.    Either way, Republicans are sharpening their knives, knowing that voters are angry at the spending habits of a Washington run entirely by Democrats (no matter that former Pres. George W. Bush and his party also contributed to the rising tide of red ink).

And that has to leave one senior appropriator, Sen. Patty Murray, D-Wash., a bit nervous. Murray is suddenly facing a more serious challenger than anyone expected from popular ‘04/’08 gubernatorial candidate, Dino Rossi, who has significant name recognition from his two failed attempts at the governor’s office.  Rossi even nudged Murray, the famous “mom in tennis shoes,” into a very rare disagreement with Senate Majority Leader Harry Reid, D-Nev., and the Obama Administration over where nuclear waste should be stored.  Murray recently advocated for Nevada’s Yucca Mountain, a political lightning rod for Reid, who has staunchly opposed such a move and is in his own difficult re-election fight.

In fact, when talking with senior Republican aides on the Hill, veterans of numerous campaigns, they are much likely now to talk to you about Rossi’s chances as one where they could knock off a member of Senate leadership, than Reid’s opponent in Nevada.  The gaffe-prone majority leader, with abysmal approval ratings, was a top target of Republicans earlier this year and generic polls showed he was all but a goner, but once Tea Party favorite Sharron Angle snagged the GOP spot in a rough-n-tumble primary, Reid’s chances grew.  He has even come up beating Angle in several recent polls, a veritable political miracle.  But though Reid has a record-breaking war chest nearing $20 million and improving odds, Cook still says Nevada “remains a race teetering on the edge.”

Another target for Republicans who has shown a surprising vulnerability is incumbent Sen. Barbara Boxer, D-Calif., though she has certainly been vulnerable in past races.  Millionaire businesswoman Carly Fiorina has truly given the feisty Boxer a run for her money.  Fiorina is able to match Boxer’s sizeable cash haul, and prognosticators mark this race as a solid toss up.  This is certainly another race where the tax issue could figure prominently.

Democrats are also feeling the heat in other surprising places, like Connecticut, where another millionaire businesswoman, Linda McMahon, is vying to take the seat of retiring Sen. Chris Dodd, a Democrat. Though up against a popular Attorney General, Richard Blumenthal, stumbles by that candidate and an anti-Washington mood have put Republican McMahon on the map, for now.

As well, Wisconsin’s Democratic incumbent Sen. Russ Feingold has suddenly been hit with a challenge by an opponent who has been rising in the polls, businessman Ron Johnson, though most experts, for now, give Feingold the advantage.

And though Democrats did appear to have a shot, generically-speaking, at the scandal-marked Sen. David Vitter, R-La., their candidate, Cong. Charlie Melacon, has not yet given the incumbent much of a challenge. Instead, Vitter could be toppled by a surprise from his right, former state Supreme Court justice Chet Taylor.  But there’s so much about this race that remains up in the air, it’s best to leave it be, for now.

All totaled, that’s 11 seats Republicans have a very real shot at, but they must also perform their own political high-wire act by holding onto all five of their open seats:  Florida, Kentucky, Missouri, New Hampshire, and Ohio.  Surprisingly, that feat does appear quite possible.

Most notable on that list is Ohio and the jaw-dropping performance by former congressman and Bush Administration official Rob Portman, who is now closing in on $9 million. His opponent, Dem Lt. Gov. Lee Fisher has banked only a paltry $1.3 million, leading Sabato to predict, “If Fisher can’t show significant, speedy progress in closing the money chasm with Portman, the Buckeye State will likely move from Toss-Up to Leans Republican in the fall.”

The wild card in that list, and one that has Republicans quite nervous, is Florida.  The unexpected independent candidacy of Gov. Charlie Crist has given Tea Party darling and GOP favorite Marco Rubio a real race, and could leave the GOP with a lost seat.  The former Republican governor raked in a respectable chunk of money under his new party label, and his rather odd, public disagreement recently with Majority Leader Reid over an alleged conversation Crist said the two had about him caucusing with Democrats should voters send him to Washington (Reid denies the convo), seems to be a strong signal of Crist’s intentions to play closer to the Democrats’ line.

Certainly, a lot can happen between now and November, and the cash advantage Democrats’ national party apparatus enjoys over its GOP counterparts is certainly nothing to sneeze at.  But unless the economic experts are wrong and the jobless picture greatly improves, and Democrats find a way to sell their “tax and spend” situation closing in on them, Republicans do appear to be headed for, at the very least, a banner year.