Neoconservatives used the Republican Party as a vehicle to promote and employ their policies of muscular nation-building overseas. But like the parasite that eventually kills its host, the Republican Party’s virtual collapse, in large part because of the failed nation-building adventure in Iraq, has left neoconservatives discredited and facing policy extinction. Unfortunately, neoconservatism will probably live on by changing hosts.

Throughout American history, the structure of the political systems has ensured that only two major parties would be viable at any one time. They haven’t always been the Democrats and Republicans. They have always been the Democrats and one other party. First, it was the Federalists, then the Whigs, and finally, from just prior to the Civil War to the present, the Republicans.

The Republicans started out as a regional party of the Northeast. The only reason they ever took power away from the Democrats, the only true national party at the time of the Civil War, was because the Democratic Party split into northern and southern wings over the slavery issue. Thus, the Civil War was essentially caused by the fracture of the Democratic Party. Abraham Lincoln won the 1860 election with only 39.8 percent of the national popular vote, beating two Democrats and one minor party candidate. Southern states, fearing a Republican’s potential policies on slavery, didn’t even wait until Lincoln’s inauguration before they began to secede from the union.

Ironically, today, the Republican Party, which once had hopes of becoming the majority party in the country, has followed George W. Bush over a cliff and has once again been reduced to largely a regional party of the old South and a few other conservative states. As long as Democrats in more libertarian mountain states stand up for gun rights, most states in that entire region are ripe for permanent status in the Democratic column. The most telling moment in the 2008 election was when Arizona, the Republican nominee’s home state, was too close to call. It would have gone Democratic had a native son not been running.

If the Republican Party doesn’t now move to extinction like its Federalist and Whig predecessors, it is likely to remain only a regional party for a long while. It’s intolerant conservative social views scare most other Americans. More important, the one issue on which many Republican conservatives differed from President Bush — immigration — could be the death knell of the party. When the party alienated Hispanics (including even some Cubans, who were previously one of the most loyal Republican constituencies), the fastest growing minority in the United States, with nativist diatribes on immigration, other minorities, such as Asians and Native Americans realized that they could be victimized too. In the 1990s, Republican Governor Pete Wilson made California overwhelmingly Democratic with his immigration policies. The same has just happened at the national level. After the immigration debate in the late Bush years, it will be hard for the Republican Party to ever woo back Hispanics.

Does the long-term demise (and maybe extinction) of the GOP leave the neoconservatives up the creek without a paddle? Not necessarily.

The neoconservatives started out as liberals and socialists in the Democratic Party. They were never really that conservative on economic policy, only belligerent in foreign and defense policies. And in those two latter policy areas, the Democratic Party is still dominated by their close cousins, the liberal Wilsonian interventionists. Although the liberal Wilsonians — such as Hillary Clinton, Richard Holbrooke, and Madeleine Albright — are less unilateralist than the neoconservatives and are much more in love with international organizations, they share the neoconservatives’ passion for armed social work and nation-building. Besides, when you’re deep in the wilderness and your horse is dying, you can’t be too concerned with pimples on your new steed. The neoconservatives will probably eventually realize that the Republican Party is dying, and will seamlessly re-infest the Democratic mother ship to preserve themselves. And again, they will probably severely debilitate their host.