In a perfect world for Senate Republicans, all of the races in which they are trying to pick up seats would resemble West Virginia, where it's been smooth sailing so far.

Trouble is, they don't live in a perfect world.

It's been smooth sailing in West Virginia so far for Republicans. (Jonathan Waterman)

Before delving into the rest of the map, let's first take a look at the state of play in the Mountain State, where it’s hard to imagine events unfolding more smoothly for the GOP. First, Shelley Moore Capito, the Republican congresswoman with a well-known last name, announces very early in the cycle that she is running. Then, Sen. Jay Rockefeller (D) says he will retire. And last week, Rep. David McKinley (R) told the Charleston Daily Mail that he won’t challenge Capito, sparing the congresswoman a potentially nasty intra-delegation primary.

For the record, not all Republicans are fans of Capito. The anti-tax Club For Growth doesn’t like her. Neither does the Senate Conservatives Fund. But despite the conservative opposition to Capito, a serious contender has yet to emerge on her right. That’s also good news for the congresswoman.

On the Democratic side, things have progressed relatively slowly since Rockefeller announced his retirement in January. Former senator Carte Goodwin passed on the race, and so did his cousin, Booth Goodwin, and former governor Gaston Caperton. Rep. Nick Rahall remains a maybe. Secretary of State Natalie Tennant and businessman Ralph Baxter are also possible Democratic candidates.

To (sort of) quote Milhouse from "The Simpsons": Everything's coming up GOP in West Virginia! It sounds like a scenario Republicans should try to replicate elsewhere, doesn't it? Trouble is, that's a difficult task.

Take Iowa, a race that looked more promising for Republicans after Sen. Tom Harkin (D) announced his retirement. Unlike West Virginia, Republicans didn’t have a prominent candidate who announced a bid early. And now they find themselves facing the prospect that outspoken conservative Rep. Steve King might run, which some Republican strategists believe could doom the chances of flipping Harkin’s seat.

Aside from King, there are a handful of Republicans in other states who could foment GOP civil war, Aaron Blake recently noted in this space.

The most comparable race to West Virginia is South Dakota. There, former governor Mike Rounds, a Capito-caliber candidate, announced his bid very early in the cycle. And so far, no other serious GOP contenders have stepped up. Sen. Tim Johnson (D-S.D.) is different from Rockefeller in that he hasn’t announced that he is retiring. But Johnson is being closely watched, and might very well decide to forego a reelection bid.

It’s no coincidence, then, that South Dakota and West Virginia were the two races we rated as most likely to flip in our latest round of Senate rankings.

So, what to conclude about how Republicans should approach Senate races, based on West Virginia and South Dakota? Having a strong candidate that revs up his or her campaign early certainly helps. And little luck in the form of retirements and/or a shortage of Republicans with the capacity to trigger nasty primaries doesn't hurt, either.

And let’s not forget that in South Dakota and West Virginia, it’s been plain to see for some time that the Democratic nominees, whoever they end up being, stand to have a tough time, given the way the two states have been trending politically. That no doubt sweetened the deal for Rounds and Capito.

Senate races are discrete entities, even though the macroscopic political climate can affect them in similar ways. The Republican success in West Virginia and potential headaches the party faces in Iowa should each serve as reminders that campaigns are subject to a host of factors involving both luck and skill.