Oregon, the location Thursday's mass shooting, had recently strengthened its gun sale laws, like many Democrat-leaning states frustrated over political inaction at the federal level.
The detailed circumstances of the Oregon killing, including the identity or motive of the shooter, or the weapons used, were not yet known, other than he was a 20-year-old who died in a shootout with police.
Oregon is above average among the 50 states in terms of gun regulation, according to Laura Cutilletta, a senior attorney at the Law Center to Prevent Gun Violence, a leading advocacy group in California.
Local elected officials this year made universal background checks mandatory before the sale of any firearm in Oregon, one of 18 states to do so.
Meanwhile, sales at gun shows or on the Internet are not subject to such controls, a known loophole.
And Oregon does not prohibit the transfer or possession of assault weapons, nor does it have a gun-purchase waiting period.
Since 2013, amid Washington's inaction, several states led by Democrats passed more restrictive gun control laws.
All states have concealed carry laws which allow permit-holders to carry guns out of view.
Some are very restrictive on gun sales, including the number of weapons a person can buy, who can obtain a license, and how.
California for example bans the sale of most assault weapons and high-capacity magazines, as do Connecticut, New York and the District of Columbia, among others.
Some, like Georgia and South Carolina, have taken a more permissive route, expanding the locations for permit holders to carry weapons to include bars, churches and airports.
Texas recently legalized carrying guns on college campuses.
The reform movement has tried to counter the extraordinary influence of the NRA through extensive awareness campaigns.
The billionaire ex-mayor of New York, Michael Bloomberg, and his organization Everytown for Gun Safety poured millions of dollars into the 2014 congressional races in an effort to beat the NRA's favored candidates.
Coincidentally on Thursday, 147 lawmakers wrote House Speaker John Boehner calling for Congress to address the "national epidemic" of gun violence.
According to the Brady Campaign to Prevent Gun Violence, an average of 32,000 people died annually from firearms from 2009 to 2013, including about 20,000 suicides per year.