All who pretend to be fair-minded are obliged to admire the resilience and resourcefulness of which Democrats, still reeling from yet another pasting at the polls, are somehow capable. Prominent Democrats, cheerfully ignoring the carnage in their ranks, crow that Ronald Reagan, next January, will have fewer members of his party in the House of Representatives than any elected or reelected president since Grover Cleveland. See, exult the Democrats, our party is in good shape where it counts most -- at the local level.

What these "Norman Vincent Peale" Democrats choose to overlook is that any political party that remains noncompetitive at the national level for a generation or more finds itself almost inevitably without either philosophical cohesiveness or a farm system of talented, young candidates eager to run for office.

Consider the dilemmas of a Democratic House candidate in recent presidential years. Being a good partisan, you hope your party's nominee wins the White House. You also hope the national ticket gives you a boost in your own district. But for most Democratic House candidates over the past 20 years, that has been a futile hope. In 1968, Hubert Humphrey came within an eyelash of winning the presidency, but was able to carry only 160 House districts. In 1980, Jimmy Carter carried only 127 districts, and in that memorable year 1972, George McGovern defeated Richard Nixon in only 57 districts out of 435. In each of these three presidential elections, 243 House Democrats still managed to win election -- on their own, despite the drag at the top of the ticket.

The presidential issues -- the economy, national defense, the proper role of the federal government -- intrude upon House campaigns. GOP House candidates have generally seen political advantage for themselves in echoing the positions and the rhetoric of their presidential nominee on national issues. Such public agreement among Republican candidates encourages party unity before the election and party unity after.

For Democrats, the opposite case has prevailed: House candidates, concerned about their own elections, have chosen not to share the same platform -- either philosophically or sometimes even physically -- with their national running mates. They have had to run and win on their own, which has frequently meant an emphasis on different issues in different districts and, almost always, on independence from the national party. In the event of a Democratic presidential victory, the result is no guarantee, or even likelihood, of party cohesiveness on a program.

As the pro-politics and pro-government party, the Democrats have been able to attract as candidates a disproportionate share of those college graduates who are energetic, articulate and aggressive. In a number of strongly Republican congressional districts, Democratic representatives -- such as Les AuCoin in Oregon, Matt McHugh in New York and Tim Worth in Colorado -- have been able to win because they are superior political leaders to anyone the Republicans, with all their megabucks and state-of- the-art machinery, have been able to recruit to run against them.

But the Democratic farm system of youthful talent shows signs of trouble. Ronald Reagan won three out of five votes of those under the age of 30, which, if the pattern holds, can only be bad for the Democrats. The Democrats were the beneficiaries of the example of John Kennedy, whose career inspired hundreds of candidates, and of the stupidity of Richard Nixon and Spiro Agnew, whose angry attacks on college anti-war protesters helped to lose a whole generation of potential candidates for the Republicans. Nixon and Agnew made it almost impossible, because of peer pressure, for young people to be Republicans.

But that, too, could be changing as Democratic idealism and optimism have run dry. Without unity and talent, no party can long prosper.