Republicans began the year with high hopes of retaking the Senate after coming up just short in 2010. Democrats cling to a narrow 53 to 47 majority, and are defending 23 seats in November. This includes several held by freshmen who were washed in by the Democratic tide six years ago, only to face reelection under very different circumstances.

The GOP’s prospects brightened further with a wave of fortuitous retirements. Democratic incumbents decided to call it quits in Virginia, North Dakota, Nebraska, Wisconsin, and New Mexico. In some of those cases, they were replaced with weaker Democrats.

Democratic incumbents were in serious trouble in Missouri and Montana, and seemed at least hypothetically beatable in Florida and Ohio. The only vulnerable Republican incumbent was Massachusetts Sen. Scott Brown, who has proved remarkably resilient in a tough political climate and has managed to keep the state a toss-up.

Yet much like the presidential race, what seemed like it should have been easy hasn’t been. There will be GOP pickups, to be sure. The Democrats may have gotten their dream candidate to replace retiring Nebraska Sen. Ben Nelson in former Sen. Bob Kerrey. But Kerrey hasn’t won a statewide race in the Cornhusker state since 1994 and Nebraskans have only gotten more conservative since then.

It hasn’t helped that Kerrey spent a decade living in New York City, where he was president of the left-wing New School. Despite facing lesser known Republican state Sen. Deb Fischer, Kerrey has in recent months trailed by as much as 18 points. He barely breaks 40 percent in the most recent Omaha World-Herald poll. Kerrey looks like he stands no better chance than Nelson would have.

Other Republican pickups look more precarious. The Real Clear Politics polling average shows Rep. Rick Berg leading Democratic former Attorney General Heidi Heitekamp by just five points in the race to replace retiring North Dakota Sen. Kent Conrad. Montana Republican Rep. Denny Rehberg, who holds a statewide at-large seat, has even slimmer lead over incumbent Democratic Sen. Jon Tester—three points in the latest Mason-Dixon poll.

The Republican challengers are still slight favorites in both races, occurring in states where Mitt Romney’s presence on the ballot should actually help them. But their leads are much smaller than expected and the Democrats could conceivably still win those races.

In Missouri, Republicans may have blown their chances of unseating incumbent Democratic Sen. Claire McCaskill by nominating Rep. Todd Akin to run against her. Akin was considered the weakest GOP challenger even before he opened up his mouth about “legitimate” rapes rarely causing pregnancy—that’s why Democrats spent money to help him win the nomination—and his 10-point lead evaporated after those comments.

From Romney to the National Republican Senatorial Committee, state and national GOP leaders tried to push Akin out of the race. But they had nothing to give him and may have been too heavy-handed in their approach, so he stayed in past two deadlines that would have allowed Republicans to field another candidate.

As the race enters into homestretch, some conservatives and Republicans have resumed their financial support of Akin. “We support Todd Akin and hope freedom-loving Americans in Missouri and around the country will join us so we can save our country from fiscal collapse,” Sen. Jim DeMint and former Sen. Rick Santorum said in a joint statement. An Akin win isn’t impossible—alone among reputable pollsters, Public Policy Polling projects one-point race—but it’s highly unlikely.

George Allen looked like a sure bet to win back the Senate seat he—just barely—lost to Jim Webb running a disastrous campaign in a bad year for Republicans. In the elections of 2009 and 2010, the Virginia GOP rebounded sharply. But in a clash of former governors against Tim Kaine, who was also once chairman of the Democratic National Committee, the polls for months have shown a tie or a slight Kaine edge.

Allen doesn’t seem to have recovered from the damage he did to himself in Northern Virginia in 2006. He is also hurt by the fact that Romney is underperforming in Old Dominion. Allen could still pull it out—in their first debate, Kaine appeared to endorse a minimum tax for the poor in response to Romney’s “47 percent” comments while Allen avoided any major gaffes—but what once looked like a sure GOP pickup would now be considered an upset.

Republican challengers in Ohio and Florida never really caught on in the first place. On paper, Sen. Sherrod Brown is too liberal for Ohio but in practice he his populist shtick has caught on there. Florida Sen. Bill Nelson has topped 50 percent in some polls.

Their GOP opponents—Rep. Connie Mack IV (whose father once held the seat) and State Treasurer Josh Mandel, respectively—have occasionally surged in the polls only to recede again. It doesn’t help that Romney is currently trailing in both Ohio and Florida, and doesn’t seem likely to have significant coattails even if he comes back to win either state.

Republican former four-term Wisconsin Gov. Tommy Thompson has fallen behind in the Senate race against Democratic Rep. Tammy Baldwin, the latest setback in a state the GOP had once hoped to make competitive at the presidential level with the addition of Rep. Paul Ryan to the ticket. Thompson maintains that he fell behind because he was no longer on the air with ads and that he will regain his lead now that he has replenished his fundraising coffers.

The GOP is also playing defense in Maine, where moderate Sen. Olympia Snowe unexpectedly retired. Independent former Gov. Angus King is leading in a three-way race that also features a Republican and Democrat. King has said he will caucus with the Democrats if elected to the Senate, however.

A bit south of Maine, the Massachusetts Senate race remains competitive between Brown and Elizabeth Warren. Brown has shed his nice-guy image and gone negative against Warren, a risky departure from the persona that has made him a rare Bay State Republican who has never lost an election. Although Romney is a former Massachusetts governor, his presence at the top of the ticket has probably hurt Brown. Brown and Warren have been trading leads, but the incumbent has been consistently stuck below 50 percent.

When Indiana state Treasurer Richard Mourdock beat longtime Sen. Richard Lugar in the GOP primary earlier this year, it didn’t look like it would have much impact on the Republicans’ control of that seat. But Mourdock has had a tougher than expected race against former Democratic Congressman Joe Donnelly and fell two points behind him in the latest Howey/Depauw Indiana Battleground survey—even with Romney comfortably ahead in the state.

Although Mourdock won the primary by a wide margin, some of Lugar’s supporters appear to have hard feelings. According to one poll, Mourdock is winning only 71 percent of Republicans against Donnelly. Lugar has reluctantly endorsed his former primary foe, but hasn’t been active in the campaign. Unlike Akin, Mourdock is a genuine Tea Party candidate so if he lost it would be seen as a setback for the movement.

In Arizona, GOP Rep. Jeff Flake has a thinner than expected lead over Democrat Richard Carmona. A poll commissioned by a Republican-leaning firm found that Romney hasn’t put Obama away either in the state, though he is ahead. Flake remains the favorite.

Republicans have run surprising strongly Senate races in Connecticut and Pennsylvania. But Linda McMahon appears to have peaked against Democratic Connecticut Rep. Chris Murphy, while Tom Smith has only managed to move the race against Pennsylvania Sen. Bob Casey from “solidly Democratic” to “leans Democratic” in the eyes of political handicappers.

All this adds up to a Senate that isn’t much changed, with Republicans achieving a net gain of one or two seats while needing at least four if the Romney-Ryan ticket doesn’t prevail in November. As with the presidential contest, it’s still possible that things break the Republicans’ way. But it won’t be easy.

W. James Antle III is editor of the Daily Caller News Foundation and a contributing editor to The American Conservative. Follow him on Twitter.