N. Carolina political tide changes. Democrats admit that `Operation Switch,' the Republican effort to convince voters to change their party affiliation, is working

The North Carolina state Democratic Party is waging a massive campaign to keep party members from fleeing to the Republican fold. The drive is in response to the GOP's Operation Switch, an effort at the state level to attract conservative Democrats to the Republican Party.

North Carolina, the country's 10th largest state, has become a major partisan battleground. The state led all others in the proportion of hotly contested United States House of Representative races last November, with 6 of 11 House seats decided by margins of less than 2 percent of the vote.

North Carolina was one of four states targeted by the Republican National Committee for Operation Open Door, a $750,000 drive to recruit 15,000 Democrats in North Carolina and 85,000 others in Pennsylvania, Florida, and Louisiana.

The Democrats' grip on the Tarheel State has been slipping for the past two decades. The state was once a stronghold of the Democratic South with a solid base of blue-collar and rural conservative Democratic voters.

``I remember a time when our candidates were scared to identify with the Republican Party on their campaign paraphernalia and yard signs,'' says Barbara Boyce, chairman of the Mecklenburg County Republican Party.

Now Republican candidates are showing no fear in sporting elephants on yard signs for the local races in November. Boosted by President Reagan's popularity, the GOP picked up six seats in the state Senate and saw a net gain of three US House seats.

Some political analysts say that growing immigration, sparked by a high-technology boom, is hurting the Democratic Party. The Research Triangle Park, one of the world's largest scientific centers, is bringing large numbers of new residents to the Raleigh-Durham area. Raleigh has become one of the fastest growing cities east of the Mississippi.

``These new voters tend to be Republicans,'' says Merle Black, professor of political science at the University of North Carolina at Chapel Hill. ``But they don't identify with Jesse Helms and the ultra-right wing of the party.''

All of this is prompting the Democratic Party to fight back. Visiting the Democratic Party state headquarters, located in a plantation-style house inRaleigh, one finds it difficult to tell that the coming campaigns are for an off-year election.

The state party has a paid staff of 11, twice the usual number in an off-year race. For the first time in the state party's history, the Democrats have hired a youth coordinator and a congressional campaign director. Tarheel Democrats are trying to beef up party appeal to young voters and are hoping to launch a television and radio advertising campaign later this fall.

``People are saying we needed to get kicked in the rear so we would stop being so complacent,'' says Betsy Jordan-Simmons, president of the Mecklenburg County chapter of the Young Democrats. ``The Republicans are gaining and we have lost ground.''

At the center of the Democrats' campaign is the struggle to bring more young voters into the party. Last April the Democrats hired Harry Kaplan to develop stronger ties between the state party and the state's young Democratic organizations -- Teen Democrats, College Democrats, and Young Democrats. Mr. Kaplan has mailed newspapers and newsletters for all three groups, some blasting GOP Gov. James G. Martin for proposed cuts in aid to public colleges.

Kaplan says he is also planning a series of forums, featuring national leaders who are popular with young voters. New York Gov. Mario Cuomo, Sen. Gary Hart, and Jesse Jackson are among the speakers being considered.

The efforts to attract young people leave state Republicans somewhat bemused.

``We don't have to hire a youth coordinator,'' says Chris Andrews, director of communications and research for the North Carolina State Republican Party. ``We already have three strong Republican youth organizations that helped elect Martin, Helms, and Reagan.''

``The winds of change have come,'' says Robert Bradshaw, chairman of the North Carolina State Republican Party. ``We are riding the winds and they are running from them. The liberal agenda of state and national Democratic leaders is out of sync with this state.''

Still, many Democrats say the Republicans' nationwide Operation Open Door is a failure.

A local newspaper survey of county boards of election shows that the Republicans drew roughly 2,600 Democrats while the goal was 15,000.

GOP leaders claim they have identified, by phone, nearly 15,000 voters who plan to change party affiliation and say several county boards of election do not keep up-to-date records of party changes.

Even if Operation Open Door has failed, the statewide Operation Switch runs throughout the year and Democrats admit the GOP is gaining ground.

``We have more members statewide,'' says Ron Harper, chairman of the Mecklenburg County Democratic Party. ``But we're still the underdog or No. 2 when it comes to gains. But the fight is not over.''