WASHINGTON - Bit by bit, the face of Michael Dukakis morphed on TV screens into the visage of John Kerry, part of a spooky Republican ad that pegged Kerry as a "tax-and-spend" liberal.
The year was 1990, and Kerry was campaigning for his second Senate term. Since then, critics have continued to tag him with the label of reckless liberalism, and still do as he closes in on the Democratic presidential nomination.
So it's perhaps not surprising that Kerry has spent two decades walking a fine line: between being a loyal liberal and pursuing a more independent path in defiance of his party.
The Massachusetts senator has hewed closely to the Democratic line on many issues: He has backed abortion rights and gay rights, pushed for strong environmental protections and opposed many tax cuts in favor of spending on social programs. But he also has earned a reputation as an unpredictable - some say opportunistic - figure willing to part ways with his party on affirmative action, education, welfare, trade and war.
Kerry's supporters say his record shows he is a thoughtful, broad-minded person. He considers and reconsiders his positions, they say, unafraid of the political consequences.
His detractors call Kerry a calculating chameleon who takes stances based on political circumstance. President Bush has seized on that interpretation, joking in a recent speech to Republican governors about Kerry's "diverse opinions."
Critics point to Kerry's votes for the anti-terror Patriot Act, Bush's "No Child Left Behind" education bill and the resolution authorizing the Iraq invasion - all of which he has since repudiated. Kerry says he reversed himself because Bush broke his word on those measures.
"The charitable view of Kerry is that he understands the complexity and, in a lot of cases, the changing nature of these issues, so his positions evolve," said Paul Watanabe, a political science professor at the University of Massachusetts. Critics, he added, "say that he sort of puts his finger in the air and decides at one point in time this is the position to take, and at another time decides that's the politically safe position to take, and then is on all sides of every issue."
The criticism could be damaging to Kerry in a match-up against Bush, who tends to highlight his resolve as a steady leader in tough times.
"John Kerry finds two sides of every issue," said Kevin Madden, Bush's campaign spokesman. "The president shows leadership on these issues and makes decisive decisions based on his core convictions. John Kerry makes decisions based on political expediency."
Kerry's tendency to break with the Democratic mainstream is not new. When he came to the Senate in 1984, Congressional Quarterly said he "prefers to be known as an independent rather than liberal." From the start, he toiled to escape the shadow of the senior Massachusetts senator, Edward M. Kennedy. "John is and always has been an outsider," said Dan Payne, a Democratic consultant who has advised Kerry.
"He doesn't try to fit into the club, and he has a contrarian streak where he likes to challenge conventional wisdom. You always know where [Kennedy] is, you always know what he wants to get done, and he's 100 percent predictable. Well, the idea of being 100 percent predictable goes against Kerry's grain," Payne said.
Kerry rose through the Senate ranks not by establishing himself as a leader on his party's agenda - health care, education and civil rights, for example - but through his interest in foreign policy and his role in high-profile congressional inquiries.
Kerry led a probe in 1987 into possible links between drug smuggling and illegal shipments of weapons to the Nicaraguan contras. That led to a broader inquiry into the Bank of Credit and Commerce International scandal. The bank was found to have helped Manuel Noriega, the former Panamanian dictator, hide drug money.
Kerry has often sided with the most liberal members of his party. He voted five times against a ban on a procedure its opponents call "partial-birth abortion." And he opposed - as only 13 other Democrats did - the 1996 Defense of Marriage Act. That law defined marriage as between a man and a woman and said states don't have to recognize gay marriages performed in other states.
He has been more conservative on trade and fiscal matters. He broke with his party to back a deficit-reduction bill in 1985. And he resisted the liberal line on certain tax cuts: He backed a research and development tax credit and a cut in taxes on corporate dividends.
Kerry also supported some trade-liberalizing steps: the North American Free Trade Agreement, an African and Caribbean pact, and "fast-track" presidential authority to speed trade deals through Congress.
Kerry seems to be rethinking some of those positions. When Bush proposed a similar dividend tax cut last year, Kerry opposed it. He says he would "fix" NAFTA if elected president to keep it from sending jobs out of the United States. He says he would insist that future trade deals include labor and environmental standards.
Kerry has also broken with his party on some social issues. He raised hackles in 1992 when he gave a speech challenging affirmative action, which he called "inherently limited and divisive." He faulted politicians, "particularly in my own party," for being afraid to rethink the program.
Kerry now describes his remarks not as an attack on affirmative action but an effort to reconsider what form it should take to help minorities succeed. Still, his speech bred suspicion among civil rights leaders, some of which lingers.
"I don't think he's a person who should be taken for granted by liberals, although he has liberal bona fides," said Laura W. Murphy, the legislative director of the American Civil Liberties Union. "He has this style that's gotten him into trouble in the past, which is to sort of openly raise questions about positions he himself has adopted."
Kerry upset liberals by backing Clinton's welfare bill in 1996. He irritated them again in 1998 by proposing a plan to treat every public school as a charter school - a sharp departure from Democratic principles.
Whether Kerry's breaks from his party's mainstream have stemmed from principle or political expedience, they might have given Republicans ammunition to use against him this year.
Standing beside a stack of congressional records meant to represent the 6,300 votes Kerry has cast in the Senate, GOP National Chairman Ed Gillespie pointed to what he said was a pattern of inconsistency in the senator's record. "There are any number of things where Senator Kerry has gone back and forth on issues and raised a credibility question," Gillespie said.