WHICH PRESIDENTIAL candidate is entitled to the second-biggest amount of federal matching funds? The answer is Pat Robertson. Yet Mr. Robertson has been saying that he's not sure that he wants the money and that he may still give it back. His fund-raising statements tell us something about his appeal and how he operates.

The Robertson campaign has raised enough money privately to qualify for nearly $4.5 million in federal matching funds, second only to George Bush. It has also spent freely, on organization in Michigan and Iowa and in direct mail solicitations to the people who have given the millions. As a result, the campaign at year's end had approximately $400,000 cash on hand but owed about $1.5 million. Based on those figures, any political professional would have no doubt that the candidate would, as every serious candidate since 1976 except John Connally has, take the money and run.

But in December the Robertson forces asked for a delay to decide whether they would take the money. On Dec. 31 the request for delay was withdrawn, and this week the Treasury wired the $4.4 million to the Robertson account. But spokesmen say that the candidate may still return the money. Mr. Robertson, it is said, wants to save taxpayers' money. That strikes us as the cheapest sort of grandstanding.

What Mr. Robertson may actually be concerned about are the spending limits, reporting requirements, FEC audits and other rules that apply to any campaign that accepts matching funds; he may want to wiggle out from under these if the direct mail response is good in January (traditionally the best direct mail month of the year). But in qualifying for matching funds, the Robertson campaign has already signed an agreement to comply with the rules, and his campaign has the money in its account. Our reading of the law is that once these things have happened, the campaign is bound and cannot change its mind later and avoid the restrictions, even if it gives the money back to the Treasury.

The episode does not strengthen the case for the Robertson candidacy. His apparent indecision about accepting the money is either (a) cheap-shot grandstanding or (b) an attempted end-run around the campaign finance law or (c) an inability to meet a clear deadline to make a serious decision or (d) two or three of the above.