INDIANAPOLIS (AP) -- Three weeks before the election, Republicans are growing increasingly concerned about John McCain's ability to mount a comeback, questioning his tactics and even his campaign's main thrust in a White House race increasingly focused on economic turmoil.

"He has to make the case that he's different than Bush and better than Obama on the economy," said former House Speaker Newt Gingrich, one of more than a dozen prominent Republicans who in interviews during the past week expressed concern over the course of McCain's bid. "If he doesn't win that case, it's all over, and it's going to be a very bad year for Republicans."

Several Republicans, who spoke on condition of anonymity to avoid angering McCain, said the campaign should have sought to plant doubts about Obama's associations with 1960s-era radical William Ayers and others months ago, rather than waiting until the campaign's final weeks. Doing so now, they said, makes the 72-year-old McCain come off as angry, grouchy and desperate, playing into Democrats' hands.

Rather, these Republicans said, McCain needs to strike a balance in his tone - appearing presidential while also questioning Obama's readiness to serve and judgment to lead. And, several said McCain should close the campaign on an honorable note.

"He doesn't need an attack strategy, he needs a comeback strategy," said Alex Castellanos, a longtime national GOP media consultant who worked for McCain primary rival Mitt Romney.

The unsolicited advice comes as McCain campaign officials are becoming increasingly discouraged. From junior aides to top advisers, the frustration is palpable. Some argue the media isn't giving McCain a fair shake and are weary of the increasingly problematic environment working against the GOP. Tensions have grown over how hard to go after Obama amid concerns about irreparably damaging McCain's straight-shooter reputation.

And the candidate himself, the target of a negative whisper campaign in the 2000 GOP primary, appears conflicted on the campaign trail. He's cheery and smiling during question-and-answer sessions with crowds but becomes visibly annoyed - even surly - when he reads aloud scripted attacks on Obama and Democrats.

Despite the polls showing Obama with a lead nationally and challenging for states long in the Republican column, none of the Republicans interviewed said the race was lost. They said McCain can prevail if he presents himself as the optimistic visionary the public wants at deeply worrisome economic times.

"He needs to come forward with a serious new plan and announce it in a serious manner," said Scott Reed, who managed Bob Dole's 1996 campaign. "McCain cannot outdo Obama in just expressing outrage over Wall Street greed."

The candidates meet Wednesday in their third and final debate; it's McCain's best chance to make a lasting impression.

"He has an opportunity to step up and be a forceful leader during these challenging times," said Ron Kaufman, a veteran party operative who also worked for Romney. "McCain got the nomination because that's what his brand is, but somehow it's gotten muddled."

Senior advisers insist McCain is trying to be such a leader. They note that his daily speeches are devoted heavily to the economy, including taxes and health care, and that he's been rolling out a series of prescriptions. They complain that McCain's not getting credit for those and argue that the media holds McCain to a higher standard than Obama, who they contend is getting a free pass.

Over the past week, McCain also has been assailing Obama's character in speeches and TV ads. They include one that, with little proof, accuses Obama of lying about his association with Ayers and assails Democrats as irresponsible liberals on the economy.

Some Republicans want McCain to keep it up, though strike a balance.

Michael Steele, the former Maryland lieutenant governor and chairman of the candidate-recruiting organization GOPAC, said McCain must reassure people with a "clear and concise" economic message but also needs to "smack the other guy around a little bit."

Ohio GOP chief Bob Bennett said the campaign must do more to "close the sale" on what McCain would do as president. But he also said: "I think he needs to get tougher."

Others say the only thing McCain can do is hope Obama makes a huge mistake or an outside event changes the race.

"Winning the campaign is totally out of McCain's hands," said Matthew Dowd, President Bush's senior political strategist in 2004, who now shuns the party label.

The campaign struggled to find the right fit last week.

First, running mate Sarah Palin accused Obama of "palling around with terrorists," a clear reference to Ayers, and suggested McCain would go after Obama in last week's debate. Instead, the GOP nominee rolled out a proposal that the government buy bad home-loan mortgages. That drew the ire of conservatives.

Said Gingrich: "I can't defend it."

Last Monday, McCain gave a blistering speech asking "Who is Barack Obama" and asserting that Obama was not candid and truthful. He stood by as unruly GOP crowds hurled insults at Obama.

On Friday, McCain called for the temporary suspension of the requirement that older investors liquidate their retirement accounts - and defended Obama as "a decent, family man" the public shouldn't fear. That day, McCain's campaign also came out with its hardest-hitting ad yet.

There have been internal disagreements over how far to go, with some advisers pressing McCain to criticize Obama on his relationship with his incendiary former pastor, the Rev. Jeremiah Wright. McCain earlier had ruled that out of bounds. Some advisers fear charges of racism.

One senior McCain adviser said the worry isn't just that McCain may lose but also that, in defeat, the attacks on Obama could cause long-term damage to McCain's image.

It's not clear whether it's concern about McCain's legacy that prompted the senator to defend Obama on Friday, and advisers insisted there wasn't a conscious decision to soften the criticism. One, Mark Salter, told reporters traveling with McCain: "He responded to questions he didn't think were appropriate."

There's been backlash to the negativity.

"He is not the McCain I endorsed," former Michigan Gov. William Milliken told The Grand Rapids Press, calling the tenor disappointing. "He ought to be talking about the issues."

Perhaps no place underscores McCain's woes better than Indiana, which hasn't voted for a Democrat in decades. Obama has spent an estimated $7 million on advertising there and polls show the race is tight. Republicans just went on the air.

"He's got a great story and a great case to make," Murray Clark, the state party chairman, said of McCain. "Has he made that yet? Not really."

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