PAUL HARVEY REPORTS this "sticker snicker" from a passing bumper: "There's too much apathy in America -- but who cares?" In 1980 that question is no joke -- and neither is John Anderson's response to it. In fact, Anderson's decision to mount an independent campaign for the presidency may prove to be in the most potent antidote to apathy in recent political history.

John Anderson is a fail-safe candidate, If he wins -- an unlikely, but other, equally unlikely events already have taken place in this campaign year -- the country will be served by a man of intelligence, experience and proven capacity for coalition-building. If he loses, the country will still benefit by the demonstrated power of a third-force appeal -- the measurable expression of a new constituency for which it will behoove the existing parties to contend. Paradoxically, Anderson's best hope of winning lies in persuading his fellow citizens that, even if he is not elected, their votes for him will not be wasted.

How could voters win by casting their ballots for a probable loser? The answer lies in a specific scenario that points up the fail-safe character of Anderson's candidacy. Short of victory, Anderson is in a good position to win a sizable number of electoral votes, quite possibly enough to deny any other candidate the needed majority of the Electoral College. It is commonly assumed that such an outcome would throw the election into the House of Representatives, but that need not occur.

In these circumstances, Anderson could recommend to his electors that they support the other candidate most likely to advance the policy concerns and proposals developed in his own campaign. Holding the balance of power among the electors, he could serve his constituency best by becoming a kind of "national elector," bargaining openly with the other contenders and voicing his support for the one most willing to adopt elements of the Anderson program. The fact that this course would be unprecedent should not deter him from considering it a responsible and appropriate option.

To begin with, allowing the issue to pass into the House of Representatives would effectively disenfranchise the Anderson voters. Since House members will be party regulars, the choice there would likely fall between Carter and Reagan. Even if Anderson gains a plurality of electors, he may wish to use his power while he has it -- prior to any House action -- by forming an alliance with the most acceptable alternative.

This is not to suggest that the result in the House is a foregone conclusion. Despite the fact that most observers think that the long-standing Democratic majority will continue in the House, that body's action in choosing a president is far from predictable. Under the constitutional procedure, the House would vote not as individuals, but as state delegations. Each state would have a single vote and a majority would be required for election.

Currently, the democrats control 29 state delegations in the House, the Republicans 12, and the remaining 9 are evenly divided. But nine of the Democratic majorities are held by only one or two seats. The swing as a few as 14 seats in the proper locations could give the Republicans control of 26 state delegations, even if the Democrats retained an overall majority in the House.

Quite apart from these party-line calculations, House behavior in this situation could be influenced by the sense of moral and political obligation some members would feel to support the candidate who carried their district or state, no matter what his party affiliation. All these factors breed an uncertainty that argues powerfully for resolving the election in the Electoral College.

Some may question whether Anderson could, in fact, instruct his electors how to vote. The so-called "faithless elector" has long been a problem in American constitutional practice; indeed, one elector pledged to Gerald Ford voted for Ronald Reagan in 1976. Some states have enacted laws to require electors to support the candidates to whom they are pledged, but Neal Peirce, in a classic study of the presidential selection process, terms them "virtually unenforceable."

The Constitution intended electors to be free agents. In cases where no candidate enjoys a majority of electors, there are compelling reasons for the contender holding the balance of power to advise his supporters of his preference. Instead of frustrating the people's will, as maverick electors have sometimes done, a deliberate recommendation of this nature is the best way to insure that the ballots cast for such a candidate are fairly reflected in the final result.

In this way, Anderson and his electors could play a role similar to that originally intended for the electors described in Article II of the Constitution. They cold evaluate the other candidates on the basis of their responsiveness to the Anderson constituency's concerns and of their commitments regarding policies, programs and personnel. On the Republican side, Anderson might also try to change the party rules and structure, in particular to end the discriminatory under-representation of the more populous states in Republican committees and conventions.

The other candidates would be under great compulsion to bargain on these issues, Reagan because he might expect Carter to control the majority of state delegations in the House, Carter because he would know that the Anderson electors could swing the election to his opponent before the issue ever reached the House.

Many people have qualms about such a negotiation, but it is a perfectly orderly procedure for dealing with those instances in which no candidate and in which a post-election alliance would persist until the Electoral College acted, there should be no difficulty in completing the selection of the new president in time for a normal transition in January 1981. The Key point is that, lacking majority support, the incoming president would need wider support than he marshalled at the polls. He should be prepared to bargain honorably to obtain it.

One would not lightly empower a candidate to conduct such critical negotiations, but perhaps John Anderson's cardinal credential for the role is his avowed purpose to strengthen the two-party system, not to destroy it. His campaign will spawn no third party. It seeks to energize the existing party structures and, above all, to light the way to a more modern, competitive Republican Party.

Anderson's decision to stand for election makes sense only when measured against the sorry state of the two parties. The decline of the Republican Party, reflected less in its occasional presidential successes than in its perennial weakness in Congress and erratic record at the state level, is a clear and present danger to political stability in America. Anderson's blunt description is on the mark: We are now reduced to a "one-and-a-half party" system. It is plainly unfair and unwise to permit a party enlisting the loyalty of only 20 percent of the people to designate the principal alternative to a sitting president.

When the second party shrinks toward permanent minority status, there are but two choices for a system built around two-party competition. Either the party must be broadened from within to command sufficient standing with the voters to justify its prerogatives; or it must be subjected to pressures from without to modernize its structure and to enter coalitions with other groups in the electorate.

Chairman William Brock has done yeoman service in strenthening the Republican base. Nonetheless, the result of Brock's efforts are sufficiently problematic to warrant the judgement that an independent candidacy can apply wholesome leverage. Moderates have fled the party in recent years, and the party's future hinges on accommodating a wider, rather than a narrower, range of opinion and values.

If enough Americans rally to Anderson's standard, they will be endorsing in the most direct way his vision of an open, pragmatic Republican Party. This could reverse the decline in voter turnout (from over 63 percent of potential voters in 1960 to only 56.5 percent in 1976) and compel the reforms that could enable the Republicans to recapture the loyalty of the 30 to 35 percent of Americans who identified with them in the 1940s and 1950s.

Polls reveal that half the electorate still has formed no impression of Anderson. He is the freshest political figure on the national scene. The way remains open for him to run a campaign that will determine voter attitudes toward him as a person and as a candidate. In a political landscape littered with burnt-out cases and reeking with stale arguments, Anderson's talent for articulating the great issues before the nation could be decisive. If, when the rest of the voters form an opinion of Anderson, they react like those who have already done so, he may garner two voters in five -- a ratio that elected Abraham Lincoln and Woodrow Wilson.

John Anderson is running for president, not for elector, but voters will wish to appraise both possibilities.