The opponents of self-funders generally have to be among the best fundraisers to take advantage of the higher contribution limits the Millionaire’s Amendment provided.

According to numbers compiled by self-funding expert Jennifer Steen of Boston College, of the 93 candidates eligible for increased contributions in 2004 under the amendment, only 56 took advantage, and only 13 raised more than 10 percent of their money from those extra contributions.

Because of this, the ruling will mostly strip away one of the advantages of incumbency, as members generally raise significantly more money than challengers.

Another major way it will change the game is allowing self-funders to dump money into their campaigns without fear of what their opponents can do with the higher limits. Currently, candidates generally wait until late in the election campaign to breach the threshold, leaving their opponent as small a window as possible to capitalize.

This could lead to additional and prolonged self-funding.

Several questions still remained after the ruling came down Thursday, though, leaving campaigns in a state of limbo for now.

And before the ruling actually takes effect, a lower court will need to review the decision. That is expected within weeks.

The FEC is wrestling with how to implement the ruling. From there, the courts must deal with any challenges to that implementation.

“The main thing is, does it apply to this cycle, and if so, what happens to the money that has already been paid” above the regular limits, said Richard Hasen, an election law expert at Loyola Law School in Los Angeles.

Candidates facing wealthy opponents offered vastly different reactions to the ruling.

Rep. Kirsten Gillibrand (D-N.Y.) is preparing to face former New York Secretary of State Sandy Treadwell, who has already spent $950,000 of his own money on the GOP primary in her district. Within hours of the ruling, her campaign sent a fundraising e-mail to supporters pleading for help before the June 30 deadline for second-quarter financial reports.

“One of Kirsten's millionaire opponents has alluded he will spend ‘up to five million dollars’ to run against her,” Gillibrand finance director Ross Offinger wrote. “With the court ruling in favor of millionaires, there is nothing stopping him from writing his check now.”

Gillibrand would benefit more than most from increased limits. In the entire House this cycle, only Rep. Charles Rangel (D-N.Y.) raised more money than she did through March 31.

A similar fundraising letter was sent Thursday by wealthy Rep. Vern Buchanan’s (R-Fla.) opponent, Democrat Christine Jennings. Buchanan spent $5.5 million of his own money on his 2006 open seat race against Jennings.

Conversely, the campaign of Florida GOP congressional candidate Gayle Harrell said the ruling affected them little.

Harrell in August will face a wealthy primary opponent who has no triggered the Millionaire’s Amendment yet. About one-fifth of the $550,000 she raised through March 31 came from people contributing the maximum $2,300.

“We’re a small-donor campaign and a grassroots campaign, and that’s why we’re going to win it,” campaign manager Anthony Bonna said. “We’re a campaign that’s doing more with what we have.”

Even incumbents sometimes don’t take advantage. The Supreme Court on Thursday ruled in favor of congressional candidate Jack Davis, who tripped the amendment in the 2004 race with his self-funding. But his opponent that cycle, Rep. Tom Reynolds (R-N.Y.), didn’t even utilize the increased limits and still outspent Davis.

One of Davis’s primary opponents this year, attorney Alice Kryzan, decried the decision.

“At a time when everyday people are struggling to make ends meet, we should be fighting to remove the influence of big money from politics rather than giving millionaires and special interests even more power over the political process,” Kryzan said.

The ruling pertained only to House campaigns, but the Senate has a very similar rule that experts say will likely be struck down as soon as it is challenged.

In Kentucky, such a ruling could have large-scale implications for the Senate race. Senate Minority Leader Mitch McConnell (R-Ky.), who like Gillibrand is one of his chamber’s most prolific fundraisers, is facing a wealthy self-funder in businessman Bruce Lunsford (D).

Lunsford’s campaign could ostensibly challenge the Senate’s version of the rule, preventing McConnell from tapping his donors for contributions several times the normal limits.

Lunsford’s campaign was noncommittal Thursday but didn’t discount its legal options.

“We understand that there are still steps that the system is taking, and so we’re just going to wait and see what happens,” spokeswoman Allison Haley said. “But no decisions have been made at this point.”

Overall, two dozen House candidates have tripped the Millionaire’s Amendment so far, but fewer than half remain after the rest lost primaries or dropped out.

Four have won their party’s nomination but haven’t crossed the threshold in the general election — Illinois Republican Jim Oberweis, Pennsylvania Republican Chris Hackett, New Mexico Democrat Harry Teague and Oregon Republican Mike Erickson.

Many other candidates have the ability to self-fund past the threshold but have not done so thus far, including several members of Congress like Buchanan and freshman Reps. John Yarmuth (D-Ky.) and Steve Kagen (D-Wis.).

Self-funders who join Congress generally don’t self-fund at previous levels, though, because they can raise much more money as incumbents.

If the ruling favors either party this cycle, it will likely be the GOP. Republicans, whose House and Senate campaign committees lag far behind their Democratic counterparts, have recruited a slate of self-funders that will help them overcome that deficiency.