Government lawyers submitted a 135-page brief Tuesday defending the constitutionality of the new campaign finance law and underscoring Congress’ proper role in drafting such regulations to prevent “monied” interests from exercising “undue influence” on federal officeholders and federal elections.

“As central participants in the federal campaign system, Members of Congress are particularly well-positioned to assess both the inadequacies of existing campaign-finance legislation and the likely efficacy and practicality of alternative proposed solutions,” Solicitor General Theodore Olson, Assistant Attorney General Peter Keisler and lawyers representing the Federal Election Commission wrote in their brief.

With little more than a month to go before the Supreme Court hears oral arguments in the legal battle surrounding the Bipartisan Campaign Reform Act, the brief provides a detailed framework for how the government plans to defend the new law in court.

“It is an effort to prevent circumvention of the established statutory scheme, rather than a repudiation of the prior legal regime,” the officials argued in the court documents.

“In particular, BCRA brings two of the most notorious efforts to circumvent pre-existing law — unregulated soft-money donations to political parties and unregulated election-related advertisements paid for out of corporate and union treasuries — within the regulatory regime and makes related adjustments to the law’s disclosure requirements and source-and-amount limitations.”

Such provisions are being challenged by an array of plaintiffs ranging from Sen. Mitch McConnell (R-Ky.) to the American Civil Liberties Union.

However, Olson and other defenders of BCRA argue in their brief that the new law is far from unconstitutional and in fact “represents a refinement of pre-existing campaign-finance rules.”

In particular, they argue that the soft-money restrictions are consistent with other anti-corruption and conflict-of-interest provisions designed to protect the integrity of federal officials.

Likewise, the governmental brief asserts the electioneering communications provisions — which restrict certain issue ads depicting federal candidates within 30- and 60-day windows of an election — is “narrowly tailored to serve several compelling government interests”

Namely, they argue, the new regulations are in keeping with longstanding federal prohibitions on the use of corporate and labor funds in elections.

Numerous other proponents of campaign finance reform such as Common Cause, former Members of Congress and others also filed briefs in support of the new law.

“We’re confident that the Supreme Court will uphold the constitutionality of BCRA,” said Don Simon, Common Cause’s general counsel and author of his group’s brief. “The briefs filed today make a powerful case that this law was necessary in order to shut down the soft-money system and prevent the corruption and the appearance of corruption caused by soft money. The Supreme Court has repeatedly upheld campaign finance laws that serve these important purposes.”