WASHINGTON (CNN) -- President Theodore Roosevelt is generally credited with launching a nationwide push for campaign spending reform. Embarrassed by disclosure of secret donations by insurance firms to his 1904 election, he supported congressional efforts to ban corporate dollars in national races.
President Theodore Roosevelt supported congressional efforts to ban corporate donations to national races.
The fallout of the Watergate scandal -- and stories of secret slush funds and campaign dirty tricks -- promoted another round of reform.
The Federal Election Commission -- an independent regulatory agency whose members are appointed by the president -- was created in 1975. Its mission to oversee campaign spending is threefold: to enforce who can give, how much they can give, and how those donations are disclosed.
The high court at one time had supported government regulatory efforts. In 1990, the justices backed state laws preventing corporations from using what the majority called "the corrosive and distorting effects of immense aggregations of wealth" to support candidates, largely through its own advocacy ads. The ruling required the money to come only from a group's closely-regulated political action committee (PAC), not directly from so-called "general treasury" funds.
The idea was to ensure corporate money was not spent on election-related issues that union members, shareholders, and employees might oppose. PACs are funded only through individual donations.
And in 2003, the justices upheld the landmark Bipartisan Campaign Finance Reform Act of 2002, known to many as the McCain-Feingold law, which took effect the day after the November 2002 elections. Among its many provisions were a ban on "soft money" (unlimited and unregulated contributions to national political parties); a ban on advocacy ads (those criticizing or supporting a candidate's stand on an issue) 60 days before an election; and contribution limits and donor disclosure requirements.
Supporters of the law say it was designed to prevent corruption in politics. Opponents said it would criminalize free speech and association. Since its enactment, the high court has written 22 opinions trying to interpret the law.
Since then, the conservative court majority has slowly chipped away at the muscle behind McCain-Feingold. Wednesday's arguments could be a bold step at erasing much of the reform efforts, leaving federal campaigns more open to unfettered messages promoted by corporate, union, and issue-advocacy groups.
During those oral arguments, lawyers for Sen. John McCain, R-Arizona -- who backs reform -- and Senate Minority Leader Mitch McConnell, R-Kentucky -- who opposes it -- each will get separate time to plead their case.