purred by Senator John McCain's post-New-Hampshire, pre-South-Carolina momentum, nearly 30,000 Massachusetts voters have switched their party registrations in time for the March 7 primary, Secretary of State William Galvin said yesterday.
Mail-in registrations are still trickling in, Galvin said, but as of yesterday, slightly more than 4,000 Democrats reregistered as Republicans; about 2,800 independents switched to the GOP; and about 21,700 Democrats reregistered as independents.
Only Republicans and independents can cast ballots in the Republican primary.
It's an ''extraordinary'' shift, Galvin said, that could affect Massachusetts' primary results. Four years ago, 276,000 people voted in the state's Republican primary; if the same number of people hit the ballot booths this year, newly eligible voters will make up about 10 percent of the voting pool.
But turnout will likely depend on the results of today's contests in Michigan and Arizona, Galvin said. If either McCain or Texas Governor George W. Bush emerges as a big winner, he said, interest in Massachusetts could wane.
Still, the 2000 primary registration switch is a remarkable event, Galvin said - the first widescale shift since the odd Massachusetts gubernatorial election of 1990, when Republican William F. Weld faced Democrat John Silber, and each attracted voters from the opposite party.
Before the recent switch, 49 percent of Massachusetts voters were registered as independents, 37 percent were registered Democrat, and 13 percent were registered Republican.
Word of the massive voter shift began to spread Wednesday, the deadline for mailing registration forms or switching parties in person at local election offices. Election commissioners reported long lines at their counters and said many voters declared they wanted a chance to back McCain.
But that was before Bush's big win in Saturday's South Carolina primary, which took some of the wind from McCain's campaign.
Now, Galvin said, it's unclear whether the euphoria McCain inspired with his New Hampshire primary victory will persist two weeks from today - and whether the people who registered this month will make it to the polls.
''We could have a lively primary here,'' Galvin said. ''But if the Republican contest begins to fall apart, that will obviously reduce the turnout.''
