Jack Cafferty asks the question on his CNN blog about the future of the Tea Party. I was just about to blog about that and see no reason not to post a paragraph on his blog and more on this one. The Tea Party, at least at the leadership level, is Republican astroturf goaded by one of your main competitors. It was never anything but a GOP activity designed to rally the base, especially the economic conservatives. The poll should have asked what Republican party offices activists have held in the past if you really wanted to know the true nature of the "movement." Now, there is a thread of people who want both more economic justice and less government who the movement was gunning for, but the reason they were being mobilized was to revitalize the GOP, not form a third party. Time will tell whether the GOP gets them or not.
Carl Milsted believes that the most fertile ground for a new party are members of the Christian Left and people that can be classified in his political matrix as "Left Leaning Freedom Lovers" which would support a mix of libertarian and democratic policies, as well as "Social Liberals", which favor a mix of Libertarian, Green and Democratic views. When I took his political quiz, I lined up right on the line between these two groups, neither of which is really represented by either party. From its stated positions and past support for Constitution Party folks, it is more likely that Tea Partiers would fit in Carl's Economic Conservative category, which is quintessentially Republican (although many hard core Republicans are in his Social Conservative area - however these care less about taxes than abortion, gays and immigration).
My bet is that many of the people who are liking the Tea Party (outside its Republican organizers) want more economic freedom but are not necessarily happy with the Republican social conservatives. The Republican Party will never be a home for these people, although they may vote Republican if Obama does not get the economy back on track soon. Of course, if the immigration debate comes to a head, they may just stay home if the Republican social rhetoric gets ugly (which it likely will).
The recent losses in Virginia, New Jersey and Massachussets did not come because the Republicans are gaining in popularity, but because the new Obama voters stayed home or have moved, graduated or were not mobilized on election day. In time, these voters will turn out more frequently while the older Tea Partiers continue to die off (sometimes in a blaze of infamy). Anchor babies will also soon age into the voting population, even without immigration reform. I doubt they will vote with Republicans who wish to deny them their natural born citizenship.
Indeed, freedom lovers will tell you that the best way to reduce immigration is to quit restricting the ability of immigrants to work. They will then become less attractive to American employers because they cannot be exploited if they no longer need documentation (or if they, gasp, join the Union like American workers).
The Tea Party may force a third party, but only because they contain enough anti-immigrants to make the GOP look like the KKK, while at the same time radicalizing people who want both more freedom and more justice (the Christian Left and Christian Libertarians). Even if the Christian Left does find a home in the Democrats (like we did in 2008), we won't stay there and the Democratic Party and the ranks of the independents will eventually get too big to not lead to a third party by 2016, except that this "third party" will likely be a second party by then. It all depends on the positions held by the two top contenders to replace Obama that year. Whoever loses the nomination may take their marbles and go found a second party. My bet is that the Democrats will fracture on corporatism vs. populism, what to do about the deficit and abortion. That's 2016, however, not 2010.