One of the benefits of being a member of Congress is that you very rarely have to put your money where your mouth is. Or, given that we're talking about voice votes in our donor-saturated system: Congress rarely has to put its mouth where its money is.

Of all of the diverse things on which a senator or representative takes a stand over the course of his or her career, only a percentage ever actually come up for a vote, and only a subset of those mandate taking a position that leaves no wiggle room. Politicians, being politicians, are perfectly content to have that be the case.

Over the course of a long career, though, that becomes harder. Meaning that during their 36 and 24 years respectively, Joe Biden and Bernie Sanders have established more robust records on gun issues than most legislators -- including Hillary Clinton.

On Monday, Clinton addressed recent incidents of gun violence and offered a number of proposals meant to limit access to firearms. Included among them was a promise to use executive action to identify high-volume sellers at gun shows as firearm dealers, subjecting their sales to background checks.

When she was in the Senate, Clinton repeatedly co-sponsored legislation that would have required background checks at gun shows, including signing on to a bill introduced by Sen. John McCain (R-Ariz.). Since Clinton's service was during closely split or Republican-controlled Senates, she didn't have many opportunities to vote on legislation that would have expanded background checks or introduced other new restrictions on gun possession. She's often discussed the issue, but much less often been forced to vote on it.

There was one major gun issue on which she and her two opponents (should Biden run) all weighed in. In 2005, Congress once again took up the question of whether or not to block class-action lawsuits against gun manufacturers. (Similar legislation failed in the Senate in 2004, with Clinton and Biden joining a large majority.) The bill passed the 109th Senate by a margin of 65=31, with Biden and Clinton again voting "nay." In the House, it passed 283 to 144, with 59 Democrats bucking their party to support the bill. The sole independent in the House also supported it -- that being Bernie Sanders, who hadn't yet been elected to the Senate.

Earlier this year, Slate's Mark Joseph Stern referred to that vote by Sanders as being for "the most reprehensible pro-gun legislation in recent memory." But Sanders, Stern acknowledges, had an existing record of support for gun owners and opposition to expansions of gun regulations. As our David Fahrenthold noted in July, the NRA actually helped Sanders get elected to Congress.

"Bernie Sanders is a more honorable choice for Vermont sportsmen than ­Peter Smith," now-NRA head Wayne LaPierre wrote in 1990.

The NRA got a few good votes out of Sanders in the House. In 1993, he opposed the Brady bill, one of the most contentious pieces of gun-control legislation in recent history. In doing so, he joined about one-quarter of House Democrats. On the Senate side, the bill passed with an even larger percentage of the Democratic majority, including Joe Biden. The bill was signed into law by President Bill Clinton, establishing federal background checks on firearm sales. (On her Web site, Hillary Clinton notes that she "strongly defended" the bill.)

An ad from a super PAC backing Martin O'Malley.

By the end of the second Clinton administration, the debate was over closing the so-called gun-show loophole. A Senate amendment to a school safety bill that would have closed the loophole passed with former vice president Al Gore breaking a 50-50 tie. Biden voted for the amendment, but the legislation never passed the House. On the House side, Republicans introduced a bill that would have limited what counted as a "gun show" for the purposes of introducing background checks. Sanders opposed the bill, which failed.

In the wake of the massacre at Sandy Hook Elementary School, Sanders voted with the Democratic majority to try and regulate high-capacity magazines and reintroduce the assault weapons ban (which he and Biden supported in 1994). He also voted for cloture on a filibuster of an amendment that would have introduced background checks at gun shows -- which, translated from Congressese, means that he supported the amendment. The filibuster of the Manchin-Toomey amendment held, effectively ending the push for new gun legislation in the wake of Newtown.

Should he run for the Democratic nomination, Joe Biden has a less contentious record to deal with. In 1986, Biden did vote for the Firearm Owners' Protection Act, which blocked a federal gun-owner registry and introduced a number of other reforms to the Gun Control Act of 1968. The NRA Institute for Legislative Action referred to the bill  in a 2011 article as "the law that saved gun rights." The vote in the Senate wasn't particularly close, it's worth noting; Biden joined two-thirds of the Democratic caucus in supporting it.

It remains to be seen how much Democratic voters will focus on gun control in their 2016 votes -- and the extent to which Sanders's past positions will affect their decisions. As we noted last week, Democrats are far more likely to express a desire for stronger gun laws than Republicans...

...though gun-control supporters have expressed less willingness to punish those tho vote against them.

The politics of Clinton's announcement are obvious. By calling attention to gun-control measures, she can draw a distinction between her record and Sanders's. In an interview with MSNBC the night of the Oregon shooting, Sanders positioned his views as being an attempt at finding middle ground. "You got a whole lot of states in this country where people want virtually no gun control at all," he said. "And if we are going to have some success, we are going to have to start talking to each other."

On Monday, responding to Clinton's proposals, Sanders put forward ideas of his own.

But still, Sanders is at a disadvantage in a match-up with Clinton on gun control -- that same disadvantage that so many politicians want to avoid.

He has a voting record to look at.