The uncertain political odyssey known as the New Hampshire primary comes to an end Tuesday amid a predicted light snowfall and a flurry of final campaigning.

The last hours of the Republican campaign were marked by a long-distance exchange of charges between George Bush, who is relaxing in Houston, and Ronald Reagan, who is campaigning here. Essentially, each candidate accused the other of being responsible for excluding four other GOP presidential candidates from a Bush-Reagan debate in Nashua last Saturday night.

On the Democratic side, Sen. Edward M. Kennedy and California Gov. Edmund G. (Jerry) Brown Jr. campaigned in New England throughout the day, while aides of President Carter attempted to convince reporters that their internal polls and phone samplings pointed to a victory much narrower than the lopsided margins indicated in published surveys.

There was some concern in the Carter camp that the latest consumer price index and the latest failure to obtain release of the U.S. hostages in Iran may have dramatized frustrations about Carter's policies. But as he has done so often in the past, Carter immediately attached himself to a powerful positive national symbol, the U.S. hockey team that won an Olympic gold metal Sunday after defeating the Russians two days earlier.

"When the goalie wrapped himself in the American flag, you know where he learned the trick," a Carter aide said Sunday.

The politics of patriotism, sometimes working succesfully and sometimes not at all, have been a staple of the seven primaries that have given New Hampshire a disproportionate place on the American political map during the past 28 years.

Though New Hampshire chooses only 19 of 3,331 delegates to the Democratic National Convention and only 22 to 1,993 Republican delegates, this tiny primary is once more likely to exercise an enormous influence on the bigger primaries ahead.

Candidates who do poorly here with the media spotlight upon them often find it difficult to raise money for future campaigns.

For Republican Bob Dole, who has been campaigning here between Senate duties since May, this first state primary could also be the last. So could it, also, for Democrat Brown, who has lost most of his top staff, including long-time aide Tom Quinn. Republican Philip Crane, who shows negligbly in preelection polls, is expected to last through the Massachusetts primary a week later but needs a strong showing here to survive.

Though New Hampshire continues to be a political graveyard for candidates who cannot find the right combination of fund-raising, organization and media proficiency, there are differences between this primary and primaries of the past.

One difference is that New Hampshire is not really first anymore. It has been preceded by the Iowa caucuses and then by the Democratic caucuses in Maine and the Republican primary in Puerto Rico. Insted of starting from scratch here, the winners of the earlier tests (Carter and Bush) come to New Hampshire with confidence, media attention and high expectations. The losers of these earlier tests find themselves seeking to recover instead of to begin.

Another difference this time is New Hampshire itself. Enjoying a business boom prompted by its lower taxes, the state has attracted droves of residents from neighboring Massachusetts and with them the familiar urban problems of smog, water pollution, litter and crowded highways. While New Hampshire is no microcosm, it is now more representative of other eastern states than it has ever been.

The primary ballot also has taken on a modern shape. Gone are the long list of delegates, pledged and unpledged which confounded counting and sometimes skewered results. This time, voters will mark ballots or push levers for the candidates of their choice, and the delegates will be selected by the candidates afterwards.

The X-factor in New Hampshire is the Independent voter, who may participate in either primary. Carter is strong among Independents, but the fear in the Carter camp is that Independents will prefer to vote in the red-hot GOP primary.

Bush has been banking on these Independents, partly because Reagan has strength among traditonal Republicans. Now, there is concern in the Bush camp that some Independents may drift to Illinois Rep. John B. Anderson, who has waged a lively, liberal Republican campaign. Since "fair play" is a strong value among Independent voters, the Bush organization is working hard to clear their candidate of suggestions he didn't play fair last Saturday when the Nashuya Telegraph refused to convert the two-man debate into a free-for-all.

Reagan, who was paying the cost of the debate, tried to open it to Anderson, Crane, Dole and Sen. Howard H. Baker Jr. All of these candidates except Crane wound up blaming Bush for their exclusion.

Today, in interviews and a statement, Bush said he had been willing to broaden the debate to include other candidates and that he wished in retrospect that he had met with the others before the debate as they had requested. But Bush said that Regan had never contacted him personally about enlarging the debate and said Reagan had "sandbagged" him.

"Frankly, I feel he used you to set me up," Bush said in a letter sent to the four GOP candidates excluded. Regan, informed of Bush's statement while campaigning, called it "ridiculous" and said of Bush's accusation: "I'm sorry to hear that. I thought better of him."

This morning Reagan was asked whether to so-called 11th Commandment -- Thou shalt not speak ill of a fellow Republican -- had been shattered.

"Maybe cracked a little bit . . .," he replied.

But amidst the criticisms of each other's conduct, both candidates continued to insist that they would follow the 11th commandment's dictates.