A month after the 1999 mass shooting at Colorado’s Columbine High School in Colorado, the U.S. Senate approved an amendment to require background checks on all buyers at gun shows. “The vise lock that the NRA has had on the Senate and the House is broken,” said Sen. Charles Schumer (D-NY). His prediction was wildly off base, says the Los Angeles Times: The measure was doomed. Gun control advocates again claim momentum for tighter regulations, but the failure of the post-Columbine effort underscores the challenges gun check proponents face today after the Newtown, Ct., school shooting. In 1999, Republicans, largely skeptical of stricter gun laws, narrowly controlled the House, but now they hold a substantially larger margin. The National Rifle Association, which supported more background checks after Columbine, now opposes them. Now, the ranks of gun control advocates are better organized, they are more politically savvy and, thanks to supporters such as New York City’s billionaire mayor, Michael R. Bloomberg, have money to compete with the NRA’s $200-million-plus annual budget.