Judging by their campaign platforms, they wouldn’t be out of place in the 5th District, home to Iowa’s arch-conservative representative, Steve King.

But here they are, in the 2nd District Republican primary, jostling for the chance to unseat Democratic incumbent Dave Loebsack.

There’s Steve Rathje, who proudly proclaims on his website, “I will not support amnesty, and I will not trade one single American life or the life of a legal immigrant for that of some common criminal or potential terrorist who chooses to sneak across our borders.”

And then there’s Mariannette Miller-Meeks, who ran against Loebsack in the 2008 general election and has adopted a sharper, more caustic tone. In an appearance at the Cedar Rapids Tea Party last September, the Ottumwa ophthalmologist questioned the constitutionality of health-care reform and talked of overthrowing elected officials.

Rounding out the Republican field is Christopher Reed, who has a staff member who worked for anti-immigrant demagogue Tom Tancredo during the former Colorado representative’s presidential campaign. Reed is perhaps best known for calling Sen. Tom Harkin, D-Iowa, the “Tokyo Rose of Al Qaeda” in his 2008 run for Senate.

Moderate bunch, huh?

It goes without saying that this cadre of conservatives holds political views unlike my own. But, ideological differences aside, I question the political viability of the primary winner in the general election.

I’m not one to shill for conventional wisdom, especially in politics. Too often it centers on the standard Democrat-versus-Republican dichotomy and, in doing so, underplays the nuances in politics. This can fuel perfunctory participation with easy-to-categorize analyses and hackneyed paradigms.

But you’d think GOP candidates would at least be cognizant of what plays politically in the area they hope to represent. It’s politics 101: Candidates have the best chance of winning when their positions are closest to that of the median voter.

In the 2nd District, where Democrats outnumber Republicans by almost 60,000 — and where Johnson County, arguably the most left-of-center county in the state, is located — the political ethos is decidedly liberal. So GOP candidates must run as moderates, much like Republican and longtime 2nd District Rep. James Leach successfully did.

Candidates in both parties always appeal to their respective bases in primaries (the median voter is decidedly more liberal or conservative depending on the party primary). Then, in effort to appeal to more moderate voters in a general election, they often temper the ideological slant of their positions and rhetoric.

But Republican-primary candidates will have to employ more than a measured jaunt back to the political center when they’re out in Steve King territory.

“Unless anti-incumbent fever is pandemic in 2010, if the GOP veers too far to the right, it would probably not only lose but lose in a landslide,” Iowa State University political-science Professor Steffen Schmidt told me in an e-mail.

Loebsack, who is vying for his third term in 2010, has an incumbency advantage and is winning the fundraising race. Through Dec. 31, 2009, the former Cornell College professor had $336,311 on hand, according to the Federal Elections Commission.

Almost 60 percent of that total came from political-action committees, a dubious distinction for Loebsack, who is on record as supporting campaign-finance reform. Rathje, the leader among his Republican adversaries, had just $46,242 on hand, almost entirely from individual contributions. The nonpartisan Cook Political Report classifies Loebsack’s seat as solidly Democratic.

Still, there’s anti-government sentiment across the country. Won’t this affect the median voter in the 2nd District? It’s likely — but not enough to completely transform the ideological makeup of the district.

I’m guessing that Rathje, Miller-Meeks, and Reed are banking on just that. Naïvely vivified by Tea Party outrage and zeal, they’ve apparently forgotten which congressional district they’re running in.