One political operative for President Carter calls it "a war." That is undoubtedly an overstatement, of the kind political agents are given to, but it illustrates the White House attitude toward its approaching confrontation with supporters of Sen. Edward M. Kennedy (D.-Mass.).

This first direct showdown will occur in polling places in Florida's 67 counties on Oct. 13. On that day, Democrats are invited to turn out for party caucuses in each of the counties and vote for delegates to the state's mid-November Democratic convention.

Both sides are out to win a majority of the 800-plus convention delegates. For Carter, the caucus test is particularly important because of the widespread impression that Kennedy can defeat him nationally and because this first confrontation takes place in a southern state that borders Carter's native Georgia and was a key to his gaining the Democratic nomination in 1976.

It is, on the surface, a meaningless political event. The delegates chosen in the caucuses will account for only about half the total at the state convention, the others being party or elected officials and people appointed by them. And while the state convention will endorse a candidate for the Democratic presidential nomination, it will have no direct bearing on the expected Kennedy-Carter race. Florida's delegates to the Democratic National Convention, where the presidential nomination will be made, will A1 be decided in the state's March 11 primary.

But the Florida caucuses are still the first test, of a sort, and are being taken with deadly seriousness by the White House and the Carter-Mondale campaign committee.

Less than a week after Kennedy sent the first of his widely publicized "signals" that he probably would challenge Carter next year, Tim Kraft, director of the president's campaign committee, dispatch Tim Smith, the committee's legal counsel, to Florida to assess the situation.

The message Smith returned with was starkly simple: Kennedy's movement toward an open candidacy had energized his supporters in Florida and other states with existing draft-Kennedy organizations. Money and Kennedy supporters were pouring into Florida from around the country. The Carter camp had no choice but to accept the challenge and wage a major fight in Florida.

"I found that it was not the Florida draft-Kennedy committee against our state organization," Smith said. "It was the national draft-Kennedy movement against our campaign."

Smith's advice has been followed.In the last two weeks, the White House has launched a form of massive political retaliation on Florida, including:

Money: The Carter budget for the Oct. 13 caucus effort has been doubled to at least $200,000, according to Jay Hakes, a former Interior Department official who is running the Florida Carter campaign.

Manpower: Hakes' staff throughout the state has doubled and is expected to number about 20 full-time aides shortly. Three White House aides with experience in advance work have left the government payroll and are in Florida working for the campaign. Other Carter operatives in the state include Terry O'Connell, who works for Washington political consultant Robert Keefe, and John Rendon, political director for the Democratic National Committee, who resigned his party job to join the Carter forces.

Advocates: Rossalynn Carter was in Florida for a fundraiser last week, and others are to follow, including the president's son Chip, his mother Lillian, White House officials Jody Powell and Jack Watson, and Carter's special representative for the Middle East peace negotiations, Robert S. Strauss. Members of the "Peanut Brigade" -- that force of Georgians who were so effective for Carter in 1976 -- also are scheduled to visit the state.

It was not supposed to work this way. Originally, Smith said, the Carter campaign organization was geared to winning next year's Florida primary election. But then came Kennedy's statements, culminating with his admission that he is thinking about trying to unseat a president of his own party.

"Whatever we might prefer," Smith said he told Kraft, "this is going to be treated as the first test. It's the first time Carter and Kennedy have competed in an electoral context."

Smith said he returned from Florida convinced that a major effort in the caucuses was justified for another reason as well.

"The reason I came down so hart on a big effort is this," he said. "If we had little support in Florida, we might welcome them making a big expenditure of resources. But the fact is that Carter has strong support there, and it goes well below the level of politicians and elected officials."

Virtually the entire Florida Democratic establishment, led by Gov. Bob Graham, is officially lined up behind the president. Because these elected and party officials control so many of the delegates to the state convention, it is widely assumed that, come November, Carter will be endorsed. The president is so confident that he is planning to appear at the convention.

Smith argues that the outcome of the convention should not be ignored.

"The theory of the draft-Kennedy movement is that this incumbent Democratic president has no broad party support and that the party is split already. What you have in the support of all these Democratic officials is a refutation of that argument. And you can't write it off to Florida being a Deep South state or to federal largess. Florida is a highly diversified state with major elements of Democratic constituencies."

Still, as Smith would be the first to argue, before November the Carter campaign must get through the October caucuses. Meaningless or not, the outcome will be watched closely as the first tentative sign of the ability of a weakened president to withstand what many consider the advance of a seemingly invincible challenger.

"It's an opportunity against a well-funded, well-staffed and mobilized opposition to prove we can be electorally competitive," Smith said. "I think the general perception is that somebody named Carter can't beat somebody named Kennedy."

The White House and the Carter campaign committee are doing all they can to try to change that perception.