If you just prevailed in the toughest fight of your life, you would think you deserve some rest. Such is not the case for Lincoln Chafee, who leaves one battlefield victorious only to fight on another where the result is uncertain. The key in the end may be whether Republicans’ successful get-out-the-vote efforts can be expanded for the general election.

Republicans pulled out all of the stops for Chafee in his primary fight against Club for Growth candidate Stephen Laffey, believing that a Laffey win would have handed the senate seat on a platter to Democrat Sheldon Whitehouse. Chafee’s primary victory assures Republicans a shot at retaining the seat, but it is by no means a guarantee.

So how did Chafee beat Laffey? Consider the differences between the general election and Republican primary electorates. Rhode Island is perhaps the nation’s most Democratic state. Gore won it by 29 points and Kerry by 21. Brown University political scientist Darrell West notes that fewer than 70,000 registered voters are Republicans (10 percent) compared to 35 percent Democrats and 55 percent independents. And most Rhode Island Republicans do not hail from the old New England moderate Republican tradition of Lincoln Chafee and his father, John Chafee. Instead, they look a lot like your generic national Republican. That is why the conservative Laffey challenge was so threatening to Chafee and the GOP.

Fortunately for them, Rhode Island allows independents to vote in the Republican primary. National Republicans used this fact combined with their vaunted get-out-the-vote machine to entice sympathetic Chafee voters into the primary. They poured dollars and manpower into the state to identify Chafee voters and get them to cast a ballot. The message for independent voters was that they could vote in the Republican primary and immediately fill out a form to request a switch back to independent status.

Without this effort, Chafee would almost certainly have lost. Chafee trailed in several polls, and trailed more among registered Republicans, but ultimately received 34,873 votes to Laffey’s 29,500. The 64,000 total votes far surpassed the typical Republican midterm primary. When Governor Don Carcieri was running in an open Republican primary in 2002, he and his opponent received about 26,000 votes combined, fewer than Laffey himself received this year. And there is anecdotal evidence that the demand for forms that independent voters fill out to “disaffiliate” was so high that many precincts ran out.

Can this formula be replicated for Chafee in the general election? Chafee is playing on more favorable turf, where there are independents and moderate Democrats who have supported Chafee and his father for the past thirty years, and Republicans will surely rev up the get-out-the-vote machine again.

But there are also some hard realities to overcome. Even with the extraordinary turnout in the Republican primary, the total Chafee-Laffey vote was less than that of Sheldon Whitehouse in the Democratic primary, where he faced only token opposition.

In a typical competitive midterm race in Rhode Island, you should expect about 350,000 votes total for both candidates. Given the national and local stakes of the race and the intense turnout efforts, it is likely that the winner may need even more than average. Shoot for 200,000.

Even being generous, the Republican turnout effort in the primary may have yielded Chafee an extra 10,000 votes to 15,000 votes. In the general election, Republican GOTV efforts will have to generate several times more votes to make a difference.

Republicans have prided themselves on finding sympathetic voters and getting them to the polls even in very Democratic places. The Chafee-Whitehouse race will put this effort to the test.

Fortier is a research fellow at the American Enterprise Institute.