Toby Spangler grew up as one of seven children in a solidly Democratic family in Janesville, Wis., where his father was president of the government workers' union local.
Today the neatly groomed 22-year-old son is president of the Young Republicans in his new home of Santa Barbara, where he attends the University of California when he is not working for the GOP. ''I've always been a conservative at heart,'' says Mr. Spangler, a youth delegate to the Republican convention, who adds that his politics is ''not discussed much when I go home.''
Sharon Maloos, just finishing her college degree at the University of New Mexico, registered as a Republican in 1980 when she reached 18. Although her family is Democratic, she says, ''I was against Jimmy Carter. I felt he just wasn't strong enough.''
The business management major, who is an aide to her state's delegation here, says of Republicans, ''I feel they really believe in capitalism.''
Even more adamant is another young convert to Republicanism, Howard Foster, 21, son of a doctor from the prosperous Boston suburb of Newton. ''In Newton, people feel guilty about their success,'' says Mr. Foster. ''I feel no guilt. The youngest member of the Massachusetts delegation continues, ''I think that Republicans stand for self-reliance and achievement. The Democrats stand for the destruction of wealth and success through redistribution.''
Words such as these are music to the ears of Republican Party officials, whose polls show that in the competition for young voters, the GOP is winning the gold medals. The credit goes largely to the ironic fact that the oldest President in history is far more popular among the under-25 set than within his own generation.
Ed Rollins, President Reagan's campaign director, says that the President's popularity is about 60 percent among the young voters, ''much higher than ever for a Republican.''
This group is also showing a preference for the Republican Party itself. While the Democrats continue to be the majority party in the nation at large, Mr. Rollins says a GOP poll shows a GOP edge in the under-25 age group.
The rightward trend among youth, coming about a decade after college campus unrest and protests from the left, is no guarantee to the GOP. Many of the postwar ''baby-boomers'' are reluctant to identify with either party, and their voter turnout rate is low.
But the shift toward the GOP among the postwar generation is disturbing for Democrats. At the Democratic convention early this summer, House Speaker Thomas P. O'Neill Jr. of Massachusetts said the biggest challenge to his party was the need to attact younger, newly affluent voters whose parents had been lifelong Democrats.
Mr. O'Neill, in a conversation with reporters, opined that the new generation has forgotten the programs, such as veterans' benefits and aid to education, that were built by Democrats and enabled their families to prosper.
Reagan campaign director Rollins credits the widespread perception of other recent presidents as having ''failed.''
''Compare the successes of Ronald Reagan to Carter, Ford, and Nixon, and the President comes out extremely well,'' says Rollins. His statement bore out in interviews with young Republicans participating in the convention.
But these newcomers to politics also say they prefer the Republican approach, especially on pocketbook issues and the future.
''I'm very much pro-free enterprise,'' says Paul Renert, a 1984 graduate of the University of Maryland, who followed his family tradition of registering Democratic when he turned 18. After taking a college course of political philosophy, he concluded he was a conservative Republican. He now works for the Republican National Committee's radio operation.
Although the Republican swing has not touched minorities with the same effect , it has swept up Claude Allen, a black 1982 graduate of the University of North Carolina. He has defied stereotypes by becoming press secretary for the reelection campaign of a New Right leader, Sen. Jesse Helms of North Carolina. ''The Democratic Party has focused for so long on things people can't change'' such as race, says Mr. Allen. ''The Republican Party has concentrated on opportunity.''
Rep. Newt Gingrich (R) of Georgia, one of the philosophical leaders of the New Right during the convention, holds that the new generation is shifting to his party ''because baby-boomers don't think it's neat to subsidize essentially an unsuccessful and unfair welfare state.''
But he concedes that conservatives have failed to articulate ''opportunity'' for young women. Moreover, the GOP has risked alienating some by failing to support the Equal Rights Amendment and opposing abortion rights.
Mr. Foster of Massachusetts, a graduate of Brandeis University this year, says he restarted a defunct chapter of the College Republican Club in 1982. By this year it had about 50 members, he says, but only about 25 percent were women.