Now, with Vice President Al Gore gaining a solid lead both nationally and in key battleground states, those warnings seem to have been on the mark. Bush's call for an across-the-board tax cut, his signature economic proposal, might be doing him more harm than good, polls indicate, even as he intensifies his effort to sell the idea to voters.
Gore has used the tax issue to paint the Texas governor as a run-of-the-mill Republican, blunting Bush's efforts to be seen as a different, and more compassionate, GOP politician.
At the same time, there is little evidence that Bush's plan is helping win him the swing votes he needs if he is to catch Gore.
"There's a big debate on taxes in this campaign," the Republican nominee told supporters at a rally in suburban Philadelphia this week. "And I welcome the debate."
For now, though, he appears to be on the losing side.
The majority of independent, swing voters prefer Gore's tax proposals, which would benefit only lower- and middle-income Americans, to Bush's plan, which would benefit all taxpayers, according to a recent nationwide poll by the Pew Research Center.
Even Republicans have relatively little enthusiasm for the proposal, the survey indicated. Interviews with Bush supporters at the rally here, outside the Delaware County courthouse, supported those findings.
'A cut for the rich'
Dr. John Chogich, 72, of Berwyn, Pa., was typical. A staunch Republican conservative, he says he's "not averse" to seeing his taxes reduced.
But the retired radiologist, who was trying to beat the heat in his red Brooks Brothers golf shirt while holding a chilled bottle of spring water, says he wishes Bush would use the money to pay down the national debt instead.
Besides, he observes, the tax-cut issue isn't helping Bush's chances.
"I think it's being portrayed as a cut for the rich," Chogich says.
The doctor's diagnosis is seconded by independent analysts, who see taxes as a dividing line between the candidates, though other issues are more important to voters at a time of unprecedented prosperity.
Defining the debate
Every presidential campaign is, at root, a struggle to define the terms of the national debate. The candidate who does the best job of casting himself in the most positive light - and painting the opposition in a negative way - usually gains the decisive edge.
In vaulting past Bush in the most recent polls, Gore has made a variety of arguments to cast himself as a defender of working families, while describing the Texan as an ally of such unpopular interests as Big Oil and the insurance industry.
Attacking Bush's tax plan as a "giant" giveaway to the rich has been a central part of Gore's message, which Republicans condemn as class warfare. Those attacks appear to have undercut Bush's efforts to define himself as a new, more inclusive Republican in tune with middle-class concerns over education and prescription drugs for seniors.
Most voters now believe Bush is "really more conservative than he lets on," according to the Pew survey. The same poll found that Gore has managed to erase the advantage Bush once held on the issue of which candidate they thought was best able to deal with taxes.
"There are no strong signs in the poll that Bush's strategy [of portraying himself as a new Republican] has worked," says Andrew Kohut, director of the Pew survey.
Elements of plan
Last December, when Bush announced his tax proposal, it was seen as part of the overall campaign plan crafted by the governor's chief political adviser, Karl Rove, to run Bush as a "compassionate conservative."
His tax initiative notably omitted such traditional Republican favorites as a cut in capital gains and business taxes.
Instead, Bush offered a variety of initiatives aimed at helping the working poor gain access to the middle class.
But the central feature was a broad cut in tax rates, dwarfing the one the Republican Congress had passed (and President Clinton had vetoed) the year before.
Timing was telling
The timing of Bush's announcement - one day before his first debate with his Republican primary rivals - went to the heart of the plan's political architecture.
It was intended to remind Republican voters of Ronald Reagan - who pushed through a major cut in tax rates - and not of Bush's father, whose broken pledge not to raise taxes still rankles some conservatives.
It was also aimed squarely at a Republican rival, taxphobic millionaire Steve Forbes, then regarded by the Bush campaign as potentially its most dangerous primary threat.
Sen. John McCain was already emerging as the main challenger, however, and he quickly began slamming Bush's tax cut for benefiting mainly the wealthy.
The arguments McCain used to attack the plan - and to win the support of independent voters - are being echoed today by Gore.
The sheer size of Bush's tax cut - it would consume $1.6 trillion of the projected non-Social Security surplus of $2.3 trillion during the next 10 years - leaves Bush less money to spend on other priorities.
As a result, it would take longer to eliminate the national debt under Bush's plan than under Gore's.
Sticking to his guns
Top Bush campaign aides deny that it was a blunder to have offered such a generous tax cut, though some congressional Republicans have openly expressed doubts about it.
Bush "believes in it more strongly today than he did when he first put it out there," says his communications director, Karen Hughes, "because he sees the fundamental flaws in Vice President Gore's plan."
A Bush TV commercial argues that Gore's targeted tax cuts "leave out 50 million people - half of all taxpayers," while every taxpayer would receive a cut under Bush's plan, and no family would pay "more than a third of their income to Washington."
Taking a cue from Republicans in Congress, who have adopted a piecemeal approach to lowering taxes, Bush is now highlighting the more popular elements of his tax package, such as a phase-out of the estate tax and a reduction in the so-called "marriage penalty" paid by many two-income families.
Targeting the middle class
Bush advisers say that many voters are still unfamiliar with the details of his tax proposal, and other Republicans worry that he hasn't been able to boil it all down to bumper-sticker simplicity.
Bush's emphasis now is on convincing middle-income voters that his plan is best for them. When he tells the partisan crowd here that a family making $50,000 a year would have its tax bill cut in half, Lois Spencer of Ridley Park, Pa., turns to a friend in open-mouthed delight.
Afterward, when asked what issue matters most to her, the 35-year-old Republican mentions high taxes. But after reflecting a moment, she says that her top priority isn't a tax cut.
"I want them to use the money to straighten out the Social Security program," she says, "so it will be there when I retire."
Bush strategist Rove maintains that voters aren't familiar yet with the Republican's plan. "When people get their heads around it," he says, "they like it."
Besides, Bush "could care less what the polls say about it," he adds, then quotes a favorite Bush line that the test of a leader is his ability to convince people that his policy is the correct course to follow.