I've found an alternate approach to these folk that's very promising. Details below.
1. If the responses indicate a willingness to consider a Dem vote this time I pursue it with gusto. I might set the hook deeper by suggesting that all politicians, in particular ones we've supported, must be held accountable and that the only way they get the message is to be voted out of office. Better Republicans can then be found in the future to replace them, but the first step is removing the current crop of hypocrites.
2. If the response shows that I'm dealing with a social conservative who clearly believes that the Repubs as the lesser of evils and the "only hope" for advancing their agenda, then I'm going to suggest that they have an opportunity to stand up for their principles without having to vote for the Democrats. Instead, I have some literature from the Constitution Party which emphasizes "Principle over Party" and I explain that, while I disagree with the Constitution Party in its attitude toward religion in government, I prefer its commitment to constitutional principles to the corruption and dangerously unconstitutional power grab of the Republican party. I try to suggest that the minimum responsibility of a principled conservative is to vote for principled candidates and that, if all citizens did that regularly, we'd have better people in office.
3. If the response shows that I'm dealing with a tax conservative of the libertarian persuasion who buys the "Dems-just-want-to-raise-your-taxes" line, I steer the conversation to the Repub assaults on liberty, asking them about how they feel about the Patriot Act and, now, the loss of habeas corpus. I emphasize the borrow-and-spend hypocrisy of the Repubs and get them to agree that it is proof of their corruption. Once I see that the Dems aren't a viable alternative for this voter, I suggest the Libertarian party, handing out their literature as needed. As with the social conservative, I make sure that the take-away point is to vote for your principles, not your party.
4. If I sense that 3rd parties make them nervous, I suggest not voting for any national race this cycle, limiting their votes to local races involving candidates they know.
I usually finish by saying that we grassroots Dems are trying like crazy to knock some sense into our DC reps, but we need their (i.e. the principled grassroots conservatives, such as "yourselves")help to do the same in their party. I leave a sense that we're on the same team--common-sense grassroots folks--opposing the flagrant abuses of power in Washington.
This approach results in having a very high number of productive conversations about constitutional principles, political hypocrisy, and civic responsibility between an acknowledged Democratic partisan and the conservatives. Nearly every conversation ends with the voter verbally committed to some alternative to voting Republican this cycle--be it Dem, Constitution Party, Libertarian, or boycott.
I hold out hope that these alternative conservative parties might knock 20% or more off of the usual Republican vote for House and Senate numbers here in Utah. It will still be difficult for the Dems to win here, but it will give us ammo and angles of attack for the future, not to mention a glimmer of encouragement that, someday, we may be able to grab the progressive wave.
I think that this approach in other areas of the country where the Dem registration isn't so low could really add to the wave in very surprising, under-the-radar, way. It also may be just what is needed to subvert and counteract the social conservative GOTV machine of the GOP. What fun it will be if they are getting their voters to the polls so that they can vote for the Constitution Party!!