Opponents of the Bipartisan Campaign Reform Act took their first swings at the new law in the Supreme Court this week, filing their opening briefs in the landmark case that will determine how federal campaigns are funded in the future.

“Far from merely closing loopholes, the Bipartisan Campaign Reform Act of 2002 (BCRA) wholly rewrites our Nation’s campaign finance laws and works nothing less than a fundamental reordering of our political process,” lawyers for Sen. Mitch McConnell (R-Ky.) and other plaintiffs in the case argued. “While BCRA’s details are complex, the principles that it upsets are basic.”

The brief goes on to argue that BCRA “undermines bedrock constitutional principles” by contravening the separation between federal oversight of federal elections and state oversight of state elections and by treating different “actors” in the political process in a “disparate fashion.”

In particular, the brief stressed that the new law “disadvantages political parties in comparison with interest groups; television stations in comparison with newspapers; and so-called ‘attack ads’ in comparison with other ads.”

“These and other forms of differential regulation violate the basic principles of equality embodied in the first and fith Amendments,” McConnell’s legal team wrote.

McConnell and friends aren’t the only ones voicing their objection to the new law, which bans soft money, regulates electioneering communications and imposes a number of other new requirements on the political community.

Quoting from the seminal campaign finance case Buckley v. Valeo, lawyers for the National Rifle Association argued in their 127-page brief that the purpose of Title II of the new law, which restricts issue advocacy, is “wholly foreign to the First Amendment.”

Continued the NRA: “This is irrefutably clear from the plain words of the statute itself; from the floor statements of legislators who supported the measure; from the sworn testimony of BCRA’s main sponsors, who intervened in the litigation; from the law’s clearly foreseeable effect of suppressing political speech.”

The brief also takes aim at Congressional sponsors of the new law, who in legal documents of their own “candidly blamed ‘the amount of general treasury funds at the disposal’ of ‘interest groups’ like the NRA for the ‘explosion’ in recent years of issue ads — or ‘negative attack ads,’ in their vernacular,” according to the NRA.

The group went on to argue that forcing it to fund so-called electioneering communications through its political action committee “will artificially deflate its voice.”

A number of other groups not directly involved in the case filed amicus briefs in opposition to the law.

The Cato Institute and Institute for Justice filed a 35-page brief challenging the government’s notion that changes contained in BCRA were necessary to prevent corruption are both “ill-defined” and “over-inclusive.”

Moreover, the brief argues that “eliminating the mere appearance of corruption is not a compelling government interest” and that “all avenues of political expression and expressive association should receive full First Amendment protection.”

Tuesday’s filings — only a handful of which were available at press time because of a 3 p.m. filing deadline at the Supreme Court — are the first real shots fired in the brutal war of words set to play out over the course of the summer.

Defendants of the new law — including U.S. Solicitor General Ted Olson, the Federal Election Commission and Members of Congress who sponsored the original legislation — are required to file their own briefs by Aug. 5.

Both sides have until Aug. 21 to file optional reply briefs, and the closely watched court case will culminate in oral arguments on Sept. 8, before the high court is scheduled to begin its regular term.