President Obama is weighing as many as 19 different gun control measures that he could take without congressional approval, as he prepares to unveil a comprehensive plan to address gun violence amid claims from Republicans that he's overstepping his bounds. 
The president could reveal the details of that plan as early as Wednesday. During the final press conference of his first term, Obama said Monday that he will "vigorously pursue" the recommendations. 
It's unclear how many of the 19 options the president would eventually take up. Those options reportedly could include more aggressively enforcing existing gun laws and beefing up national research on guns. 
The president has already voiced support for separate legislative measures in Congress, like the renewal of the assault weapons ban. That is expected to face the toughest opposition in Congress. But Vice President Biden, who led the gun violence task force and met with the president Monday, indicated the group is also pressing for limits on high-capacity magazines -- as well as background checks for anyone seeking to purchase a gun. 
Such changes "make sense," Obama said. He said lawmakers will have to "examine their own conscience" in the debate ahead. 
But the president's push is drawing resistance from Republicans in Congress. Rep. Steve Stockman, R-Texas, is now vowing to try to impeach Obama if he takes any action via executive order.   
He called the plan to implement some controls administratively "an unconstitutional and unconscionable attack on the very founding principles of this republic." 
"I will seek to thwart this action by any means necessary, including, but not limited to, eliminating funding for implementation, defunding the White House, and even filing articles of impeachment," Stockman said. 
The White House also has been at odds with the National Rifle Association, as it tries to keep focus on gun control measures in the wake of the Connecticut school massacre. The NRA, by contrast, has called for an increase in school security and a closer look at the entertainment and video game industries. 
During his press conference Monday, Obama accused critics of his approach of "ginning up fear on the part of gun owners." 
In response, NRA spokesman Andrew Arulanandam said: "The president should go talk to the people buying firearms and ask them why they're buying firearms." 
States and cities have been moving against gun violence as well. In New York, Gov. Andrew Cuomo was poised to sign into the law the most restrictive gun law in the nation, after he delivered a fiery speech last week on the need to make changes. 
"This is a scourge on society," Cuomo said Monday night, exactly one month after the massacre. "At what point do you say, `No more innocent loss of life'?" 
The bill had bipartisan support, with the leader of the Republican-held state Senate saying it does not infringe on the Constitution's Second Amendment, which guarantees the right of citizens to bear arms. 
The New York measure calls for a tougher assault weapons ban and restrictions on ammunition and the sale of guns. It also would create a more powerful tool to require the reporting of mentally ill people who say they intend to use a gun illegally and would address the unsafe storage of guns. 
At the national level, advocacy groups have been pushing Obama to order the Justice Department to crack down on those who lie on background checks; only a tiny number are now prosecuted. Such a step has support from the NRA, which has consistently argued that existing laws must be enforced before new ones are considered. 
The Brady Campaign to Prevent Gun Violence says some 40 percent of gun sales happen with no background checks, such as at gun shows and by private sellers over the Internet or through classified ads.