At midday Friday, Sarah Palin’s book-signing road show rolled into Plano, Texas, attracting yet another of the enthusiastic crowds that have greeted her throughout America’s heartland. Many waited hours to meet the former Alaska governor and get her imprimatur on their copy of “Going Rogue: An American Life.”

On Saturday, she drew 2,200 to a suburban Washington shopping mall, despite drizzle and the year’s first snowfall.

But that night, the 2008 Republican vice-presidential nominee spoke to a far different, far more skeptical gathering as the GOP speaker at the Winter Dinner of Washington’s Gridiron Club, an organization of correspondents and columnists best known for its white-tie Spring Dinner featuring skits spoofing the nation’s politics.

Palin conveyed a sense of the incongruity of her appearance, noting: “Sometimes you just have to trust your instincts. When you don’t, you end up in places like this.”

But the evening went off well. She undertook the experience with good cheer and was greeted enthusiastically by many of the journalists, including some who undoubtedly disagree with most of her views. Indeed, her appearance opposite outspoken liberal Democratic Rep. Barney Frank helped produce the biggest attendance in years for the normally low-key event, which is confined to club members, spouses and close friends.

Members disagreed somewhat on whether she struck the self-deprecatory note that distinguished some past speakers. Several detected the angry edge of her past speeches. “To paraphrase John Kennedy,” she said, “this has to be the most extraordinary collection of people who have gathered to attack me since the last corporate gathering at CBS.”

But she certainly did herself no harm and gained respect for her willingness to show up and participate in one of political Washington’s oldest rituals.

In the end, however, Palin’s ultimate political success, or lack of it, won’t be determined by the acclaim on her book tour and from conservative pundits hailing her Gridiron appearance, nor from the skepticism of Washington pundits, nor even by her recurring capacity for controversy shown in last week’s flap in which she may — or may not — have embraced the “birther” movement.

Presidential candidacies can be crippled, perhaps even destroyed, at this early date. That may be the case with the disclosure that former Arkansas Gov. Mike Huckabee granted clemency to, among others, the man who recently gunned down four policemen in Washington state.

But the chances of most hopefuls thrive or die during the months leading up to the presidential caucuses and primaries. It’s a difficult path, as can be attested by an array of highly touted, ultimately unsuccessful candidates ranging from Phil Gramm to Hillary Clinton.

Flawed strategy, misspoken comments or the revival of some hitherto unreported incident undo candidacies more often than whether the candidate was controversial before the marathon starts.

If Palin takes the presidential path, she’ll have plenty of opportunity to prove or disprove the validity of the things her supporters and detractors have stressed since she burst so sensationally onto the national political scene just 15 months ago.

The rehashing of what she said to Katie Couric in that now famous 2008 interview will be supplanted by what she says in dozens of appearances, especially in the joint appearances — not really debates — that have become a staple of the presidential campaign trail.

They will provide her best opportunity to undo the negative impressions so many Americans have formed of her capacity for the presidency. History says first impressions often stick, but her poised 2008 debate performance against a far more experienced rival, Democrat Joe Biden, should encourage her enthusiasts.

Much may depend on the state of the Obama presidency and whether it looks as if she, or any other Republican, has a real chance of achieving the always difficult task of ousting an incumbent. Voters in both parties have sometimes proven more pragmatic than ideological, opting for candidates they think might win, like John Kerry and John McCain, rather than ones their hearts prefer.

And that will determine whether the Gridiron Club will look as farsighted in spotlighting Palin as when it featured Sen.-elect Barack Obama in 2004 or was just riding a momentarily popular wave.