1. They target guns sales to criminals in the United States
A new bill introduced this week by a bipartisan group of five senators mirrors legislation unveiled last month by the House, and has one major aim: Limiting gun-trafficking. Of special concern is "straw-purchasing" — when somebody who is legally allowed to own a gun buys a firearm on behalf of someone who did not legally obtain it. This is a big problem in urban areas like Chicago, which, despite having some of the toughest gun laws in the nation, seized 7,400 guns used in crimes in 2012. According to a study by the University of Chicago, 40 percent of police-recovered guns in Chicago in 2012 were legally purchased outside the city limits and in nearby Indiana. Mayors of other other big cities, like New York's Michael Bloomberg, have been clamoring for similar laws for years. Under the new bill, those found guilty of straw-purchasing would be subject to harsher sentences of up to 25 years. 

2. They aim to cut off Mexican drug cartels
While it's very clearly illegal to smuggle guns into the United States, the laws concerning smuggling guns out of the United States are much more vague. The new bill aims to tweak the language in existing laws to change that. This is mainly aimed at stanching the flow of guns through southwestern states into Mexico, where, according to Reuters, 70,000 people have died over the course of the six-year drug war between various cartels. Senate Judiciary Committee Chairman Patrick Leahy (D-Vt.), one of the authors of the bill, is hoping this change will give federal agents more power to fight gun-smuggling:

3. Both the House and Senate bills are bipartisan 
"To the extent that people slow down and take a look at it, read it — unless you're a gun trafficker, unless you're a person who's a straw purchaser, there's really no problem with this," said Rep. Scott Rigell (R-Va), one of the two Republican sponsors of the House bill, according to The New York Times. The Senate bill is cosponsored by Mark Kirk (R-Ill.) and Susan Collins (R-Maine), who called current laws "a slap on the wrist" that treat gun-trafficking "as if it were simply a paperwork violation."

4. A gun-trafficking bill has a far better chance of passing than other gun-control measures
The inclusion of several Republican co-sponsors and the two bills' unsympathetic targets — criminals and drug cartels — have made anti-gun-trafficking the most likely of the new gun-control measures to pass. The bills could gain steam if other Republicans, especially those in suburban and swing districts, sign on. Greg Sargent of The Washington Post sums up liberals' hopes this way:

[I]t needs to be reiterated that these are both no-brainers that don't infringe on the rights of the law abiding and are supported by law enforcement. Hopefully we'll soon see more leadership like that shown here by Rep. Rigell from a handful of other House Republicans. [Washington Post]

5. Their passage would be a rare gun-control win for Obama
Unsurprisingly, Obama supports both bills. After his passionate plea during the State of the Union that victims of gun violence "deserve a vote," this might be his best chance at passing substantive gun-control legislation, especially considering both universal background checks and a new assault weapons ban will probably face fierce opposition by conservative Republicans and the NRA.