(FORTUNE Magazine) – Before this year ends, maybe before we even know about Bush vs. Kerry, the great 20-Year War over the expensing of stock options will no doubt be decided. Yes, it was way back in the mid-'80s that the Financial Accounting Standards Board (FASB) concluded, first, that options were a compensation expense that should be recognized on corporate income statements and, second, that it would begin to study how to measure the expense. Without waiting for an answer to that thorny question, corporate America reacted in loud and sustained horror to the whole idea of expensing.

And that's where things still stood in 1993 when the board, after much noodling and faintheartedness and general delay, moved formally toward a new standard by putting forth an "exposure draft" for comment. So much for that effort: FASB's plan, as everybody knows, was scuttled by unremitting opposition from business and Congress and by SEC Chairman Arthur Levitt's failure (which he later called his "worst mistake" while in office) to back the board when the chips were down.

But as this March ended, FASB, now under the chairmanship of Robert Herz, came back with still another exposure draft intended to lead, after a 90-day comment period, to a new standard that would require the expensing of options to begin in 2005. So the battle is once again joined.

Some troops are dug into their same old positions. Tech companies, not wanting to see their earnings destroyed by option expensing, are leading the opposition to FASB's plan. Intel's Andy Grove and Craig Barrett and Cisco's John Chambers have been hard-working generals in their industry's campaign on Capitol Hill. But there are nontech companies that despise the idea of expensing too. Last year Wells Fargo was required by a shareholder resolution to ask its shareholders whether they wanted to see the company expense options. The voters said yes, 695 million shares to 487 million. Think of that; 695 million shares is nearly $40 billion of value today, lined up on the side of expensing! So how did CEO Richard Kovacevich respond to this call from his shareholders? He said, No, we're not going to expense.

Elsewhere in the corporate world the troops backing FASB have grown dramatically. Once there were just two major companies, Boeing and Winn-Dixie, that expensed options. But suddenly in 2002, with Coca-Cola providing the first fizz to this movement, all sorts of major companies--even options-loving Citigroup--announced that they would begin to expense. By now, around 500 companies, many of them large, have joined that camp.

In another remarkable shuffle, all of the big accounting firms--the Big Four now, in contrast to the Big Six of 1993--have switched from opposing expensing to backing it. Why? Probably because they did not have the courage to stand up to their clients in 1993 but are now in the interesting position of having clients on both sides of the issue. So they've come around, it would appear, to voting on the side that they always knew was right.

Naturally, Congress also has opinions. On the House side, a significant number of Representatives (many no doubt influenced by campaign contributions) think that FASB should be stopped in its in tracks. But on the Senate side, Richard Shelby (R-Alabama), chairman of the Banking Committee, which has jurisdiction over the matter, seems determined to keep Congress out of it. The setting of accounting standards, he says, "should be left to the professionals."

As for SEC Chairman William Donaldson, he said last year he was "waiting restlessly" for FASB to finish its work on option accounting. On this issue, he added, "we've crossed the Rubicon." Those are strong words, not likely to lead to a backing down. And if Donaldson holds, and Senator Shelby does, you can say hello to options expensing.

--Carol J. Loomis