The logic is not difficult:

The Tea Party’s legislative successes have helped move the center of gravity of the Republican Party further to the right.

The slate of GOP candidates are pandering to this new righter-wing base. Tim Dickinson lays this out clearly and in detail in his latest Rolling Stone piece, “The GOP’s Crackpot Agenda:“

Don’t go writing the president’s political obituary just yet: He may wind up being resurrected by the GOP itself. The Republican Party – dominated by hardliners still cocky after the electoral sweep of 2010 – has backed its entire slate of candidates into far-right corners on everything from the environment and immigration to taxation and economic austerity. Whether the GOP opts for Mitt Romney or an “anti-Mitt” is almost entirely beside the point. On the major policy issues of the day, there’s barely a ray of sunshine between any of the viable Republicans, not counting those who have committed the sin of libertarianism (Ron Paul) or moderation (Jon Huntsman). No matter who winds up with the nomination, it appears, Obama will face a candidate to the right of Barry Goldwater.

Take it from one of the most divisive figures in the history of GOP presidential politics: “Those people in the Republican primary have got to lay off,” the televangelist Pat Robertson warned recently. “They’re forcing their leaders, the front-runners, into positions that will mean they lose the general election.” Robertson knows fringe politics: In 1988, he ran for president on a platform that included abolishing the Department of Education and adopting a constitutional amendment to prohibit deficit spending. At the time, Robertson was dismissed as an unelectable candidate of the far right. Today, he would be somewhere to the left of Texas governor Rick Perry. And that way lies ruin: “You’ll appeal to the narrow base, and they’ll applaud the daylights out of what you’re saying,” Robertson cautioned. “And then you hit the general election and they say, ‘No way!’ They’ve got to stop this!”

But Republican candidates show no signs of moderating their positions. In fact, with the first primary contests rapidly approaching, all of the top contenders are tripping over themselves in a race to the far right. Herman Cain’s 9-9-9 plan kicked off a flat-tax bidding war: Perry is calling for an even more regressive rate of 20 percent, while Newt Gingrich advocates a flat tax of just 15 percent. Even Mitt Romney – who once blasted such proposals for enriching “fat cats” – now exclaims, “I love a flat tax!” The candidates have also lined up behind a host of other extremist positions: waging war with Iran, slashing or privatizing benefits like Social Security, extending constitutional rights to zygotes, eliminating restrictions on Big Oil and other deadly polluters, and freeing up Wall Street to return to the lawlessness that buzzsawed the global economy. Individual candidates have embellished this partywide radicalism with wingnuttery all their own: Gingrich calls child labor laws “truly stupid,” Perry likens Social Security to “a bad disease,” and Romney wants to privatize unemployment insurance.

To many GOP stalwarts, conditions today seem ripe for a repeat, not of the 1968 election of Richard Nixon, but of the setback the party experienced four years earlier, when embattled incumbent Lyndon Johnson won re-election in a landslide over Republican hardliner Goldwater. “I can’t imagine that we expect – even with the economic situation the way it is – anything but a Goldwater-like drubbing if we persist with these guys,” says Col. Lawrence Wilkerson, who served as chief of staff to Secretary of State Colin Powell. “Even Romney is in many ways unelectable. He’s been a hardliner during the primary on key issues – and then he’s going to do this dance where he suddenly shifts to the middle and is a centrist in the general election? He can do that – but Obama will trounce him.”

Read Tim Dickinson’s complete article here.