Washington (CNN) -- The Supreme Court has given big business, unions and nonprofits more power to spend freely in federal elections, a major turnaround that threatens a century of government efforts to regulate the power of corporations to bankroll American politics. In a 5-4 ruling, the court's conservative majority crafted a narrow overhaul of federal campaign spending Thursday that could have an immediate effect on next year's congressional midterm elections. "Our nation's speech dynamic is changing, and informative voices should not have to circumvent onerous restrictions to exercise their First Amendment rights," Justice Anthony Kennedy wrote for the majority. The conservative-led opinion radically alters the election calculus, offering greater spending flexibility for a broader range of for-profit and nonprofit groups seeking a voice in the crowded national political debate. In dissent, Justice John Paul Stevens wrote, "In a democratic society, the long-standing consensus on the need to limit corporate campaign spending should outweigh the wooden applications of judge-made rules."
