The recent mass shootings in California, Texas and Ohio have prompted Democrats to launch fresh broadsides against the National Rifle Association. Yet the NRA, which typically donates to Republicans, has actually donated to a few Democratic politicians.

And at least one of them, Rep. Henry Cuellar of Texas, doesn't plan on giving the money back, despite his party's opposition to the gun lobby.

"Why would he do that?" said Cuellar's campaign spokesman, Colin Strother, when asked whether the lawmaker will return an NRA donation or give it to charity. Cuellar received $6,950 in donations from the NRA Political Victory Fund during his reelection campaign last year. He has received thousands of dollars in donations from the group since he was elected to Congress over a decade ago.

Strother also defended his boss's record on supporting the expansion of background checks and noted that he helped pass the Fix NICS Act, which would require federal agencies to report criminal convictions to the attorney general. Those convictions are put into a background check system.

Cuellar recently voted in favor of H.R. 8, a bipartisan bill that would create new background check requirements for gun transfers between unlicensed individuals. The NRA has been against universal background checks and has been actively lobbying against the bill.

"Contributions of any size have never and will never influence his policy positions. He votes based on what's best for his district, and that includes Fix NICS and background checks." Strother said. "The people of El Paso, Sutherland Springs and all over the country deserve more than symbolic gestures, they deserve a vote in the Senate on background checks."

Cuellar's 28th district is home to Sutherland Springs, Texas, the site of a 2017 church shooting in which more than 20 people were killed.

In 2019, 62 people in the United States have been killed due to mass shootings, according to a tally by Time.

Democratic strategists believe it is time for the few members of the party who have accepted money from the NRA to give it away or risk losing their seats.

"The Democrats won't do that, stupidly, because they will look too liberal," political strategist Hank Sheinkopf told CNBC. "If you don't give it back, you will have to explain the position. The explanation in the position is really inexplainable after an event like this."

Veteran Democratic strategist Mary Anne Marsh went further and said any member of her party that accepts NRA money should not be serving in congress.

"Not one Democrat should take one dime from the NRA," she said. "With domestic terrorism on the rise and guns the weapons of choice to slaughter Americans, if you aren't doing everything to end gun violence then you don't deserve to serve in congress. Taking money from the NRA won't end gun violence but it will end your political career in 2020."

In addition to Cuellar, Democrats who received money from the NRA last cycle include Rep. Collin Peterson of Minnesota and Rep. Sanford Bishop of Georgia. All three are up for reelection in 2020. The offices of Peterson and Bishop did not respond to questions about whether the congressmen would let go of the NRA donations in the wake of the shootings.

The NRA has mainly backed Republicans running for congress. Just under $700,000 from the NRA's affiliated PAC's was disbursed to various candidates during the 2018 midterms, according to the nonpartisan Center for Responsive Politics. At least 98% of NRA contributions went to Republicans that cycle.

Sen. Ted Cruz, R-Texas, received $9,000 from the NRA's PAC during his reelection campaign last year. Sen. John Cornyn, R-Texas, who is up for reelection next year, received $4,950 from the PAC in March, according to a Federal Election Commission record. Representatives for Cruz and Cornyn did not respond to questions on whether they plan to give away the NRA money.