Updated

Right up to the day before the Nov. 2 election, voters could see television ads accusing President Bush of limiting abortion and spoiling the environment. Four groups — nonpartisan but distinctly liberal — say the rules of the campaign finance law don't apply to them, a claim no one is disputing.

NARAL Pro-Choice America (search), the Planned Parenthood Action Fund (search), the League of Conservation Voters (search) and the Defenders of Wildlife Action Fund (search) can be on the air attacking Bush and promoting Democrat John Kerry (search) when most other groups can't — and at a time when voters are paying close attention to the presidential race.

"We're going to communicate with them on the air as aggressively as we can in the last 60 days," said Beth Shipp, NARAL's political director.

In December, the Supreme Court upheld the 2002 law that bans interest group ads that identify federal candidates in the two months before a general election if they are paid for with "soft money" — unlimited amounts of corporate, union and individual donations.

But the court also affirmed that the law did not apply to "MCFL" groups, an acronym for its 1986 decision in the case of the Federal Election Commission vs. Massachusetts Citizens for Life.

The justices said at the time that tax-exempt groups had a First Amendment right to expressly advocate the election or defeat of federal candidates as long as the groups meet three criteria: they don't accept corporate or union money; they mainly have an ideological focus; and they are nonprofit organizations that don't make for-profit business transactions.

"They are groups that are political in nature, but their major purpose is not electing candidates," said Larry Noble, former chief lawyer for the FEC who now heads the nonpartisan Center for Responsive Politics.

Having an "MCFL" status meant little in practice until this year, the first presidential election season where there are limits on outside group ads. Those groups with the status can do what others can't: run ads when the airwaves are less crowded; pay for commercials with soft money and without disclosing donors; and tell the public to "vote for" or "vote against" particular candidates.

"It's the first year where this can make a demonstrative difference," Shipp said.

To claim the status, groups have to meet the criteria and identify themselves as an "MCFL" organization when they report independent expenditures with the FEC. The commission doesn't routinely review whether such groups meet the criteria unless it audits them or investigates them because of a complaint.

Conservative groups, such as the Club for Growth, National Right to Life and the National Rifle Association, have considered trying to qualify for the exemption.

"It's looking more likely that we will make the conversion. It makes sense because you have fewer restrictions," said David Keating, executive director of the Club for Growth. He acknowledged that his soft-money organization, classified under the tax code as an independent political group, may be hindered by its acceptance of corporate money in the past.

NARAL and Planned Parenthood, two abortion-rights groups that oppose Bush's policies, have touted their ability — and plans — to run ads in the 60-day window in hopes of raising more money from supporters for commercials.

"It's just another tool in our arsenal, which I think makes our case even more compelling to those donors who want to help us," said David Williams, Planned Parenthood's political director.

The Defenders of Wildlife Action Fund, which says it is focused on "stopping the anti-wildlife, anti-conservation" policies of the administration and Congress, is considering running ads in certain swing states late in the general election season, a decision that depends on fund raising, said Rodger Schlickeisen, the group's president.

The League of Conservation Voters, which endorsed Kerry in the Democratic primary, plans to run heavy levels of ads to "vigorously argue our case against George Bush," said Mark Longabaugh, the group's political director.