GOP's big lead

Ronald Reagan and the Republican Party are looking at a potential ''blowout'' election in November - a presidential victory as one-sided as Lyndon Johnson's in 1964 and Richard Nixon's in 1972.

At least that is the view from Dallas at convention time. And Dallas is a vantage point that could represent the apex of Reagan-Bush fortunes for the campaign, as GOP strategists themselves acknowledge.

There are problems with taking such moments literally, as if they reflect a lasting truth. They are glimpses, snapshots. At this stage in a campaign as few as one-fourth of voters have firmly made up their minds about how they will vote in November. Most are waiting for more insight into how the candidates compare.

One wonders whether today's apparent campaign moves in a media world of its own, detached from the process of voter decision.

Still, quite an apex it is. Not only is the Reagan-Bush ticket ahead by a dozen points in its nationwide trial heats against Mondale-Ferraro, according to both Republican and Gallup Poll counts, it is also overwhelmingly ahead in the Republican Party's state-by-state Electoral College count, the way presidents are actually elected.

In the West, Mr. Reagan leads in every state, including Hawaii. In the Midwest he leads everywhere but in Minnesota, where he has pulled even with Mondale on the Democratic standard-bearer's home turf. In the South, he leads everywhere but the District of Columbia. In the East, Reagan is ahead everywhere except Massachusetts and Rhode Island, where he is even. In other words, Mr. Reagan is not behind in any state - only in the nation's capital, which is not a state. This translates into a 509-to-3 edge for him in electoral votes, with 27 in doubt; 269 electoral votes are needed to win.

This margin is likely to change, if Democrats can get their act together. The expected course would be for the Democrats to pull even, then slightly ahead in states like New York, Pennsylvania, New Jersey.

From the Republican strategists' standpoint, the Democrats have made two key mistakes. They overestimated what Geraldine Ferraro could deliver to the ticket, and they should have focused first on solidifying their base in the industrial crescent states from New Jersey to the Great Lakes. Instead, the Democrats have attacked where Reagan is strongest, in the South and West.

We shall see how it all turns out.

Convention-time euphoria can easily skew political judgment. And the elation in Dallas this week certainly is heady stuff.

Presidential debates lie ahead - events of unpredictable political megatonnage. At some point the Democrats' sharp discomfort over the Ferraro family's financial disclosures may be behind them. The very prospect of a Reagan landslide could lead many potential GOP voters to stay home and others, in contrary fashion, to vote for the underdog to reduce Reagan's margin.

Nonetheless, this is a political high point to note. A blowout Republican victory for the presidency could cancel Democratic hopes for gains in congressional races this fall as well. It would interrupt the pattern in presidential voting of the past couple of decades: Since Eisenhower's second term, a rout has invariably alternated with a squeaker. This would make two decisive Republican wins in a row, 1980 and 1984, bolstering GOP hopes for a fundamental realignment in party allegiances - a realignment that by other measures has failed to appear.