Democrats are largely avoiding the gun issue, but some hope a new Government Accountability Office report will help tighten rules for gun shows.
Can new evidence that high-powered US firearms are fueling Mexican drug violence change the political course of gun control in Washington?
Not likely, a number of gun experts say.
The Government Accountability Office information that 87 percent of seized guns given to US authorities by Mexican officials come from the US shouldn't come as a surprise, says Bill Vizzard, a criminologist at the California State University in Sacramento. "We're the largest legal gun market in the world."
Many of the firearms used to kill thousands of police and government officials in Mexico come from gun shops and gun shows in Southwest border states, the report says.
The report acknowledges that there are significant gaps in the data. It also blames both US and Mexican authorities for the problem, citing US laws that allow "paperless" sales of firearms between private individuals and corruption in Mexico that makes it difficult for the US to help it fight the arms influx.