Michael A. Memoli and Melanie Mason have an L.A. Times post, “Gun control backers consider strategy after Senate defeat,” which provides some interesting observations. Regarding Democratic prospects for electing a more favorable Senate in 2014, the authors say,

Supporters of stricter gun laws have organization, money and — after the Senate blocked an expansion of background-check requirements — fury…What they don’t have is a clear path to changing the political arithmetic of the U.S. Congress.
None of next year’s Senate races offers a good opportunity to replace a senator who backs gun rights with one who supports tougher laws.

At present it appears that 2016 may offer Dems and gun safety reform advocates a better political landscape.”Several Republican gun rights supporters face reelection that year in states where gun control has strong voter appeal; none fitting that description is on the ballot in 2014,” note the authors.
Sen. Chuck Schumer, on the other hand, sees a groundswell of support for reform in the making. “”Things change quickly here in Washington…they’ve changed for gay marriage. They’re changing for immigration. And they will change for gun safety sooner than you think.” Then there is the likelihood of more mass shootings in the not-too-distant future, if historical patterns hold, which could help fulfill Schumer’s prediction.
But it’s not about transforming public opinion, since polls indicate 90 percent or more of the public, including hefty majorities of Republicans and even NRA members support national legislation requiring background checks. With respect to electioneering, Dems don’t have enough one-issue voters for whom gun safety trumps other issues. But it is certainly possible that the issue could rise as a political priority among swing voters, either by more tragic events, or alternatively through more effective educational outreach on the part of the white house or the Democratic Party.
There is also a possibility that fed-up Dem leaders will secure filibuster reform, which would likely insure enactment of a federal background checks. Looking towards the 2014 election, however, it’s not hard to understand why Harry Reid may once again prove reluctant to weaken the Senate minority leader’s filibuster options.
One of the key lessons of the defeat of background checks is that money and activism can trump mere public opinion — even overwhelming majorities. As J. Adam Skaggs, Sr.,. counsel for the Brennan Center for Justice at the NYU Law School explains in a NYT forum, “Last year, the N.R.A. outspent the leading gun control lobby 73 to 1. Senators facing tough re-election campaigns ignore the wishes of 90 percent of Americans because they fear the gun lobby could mount a $9 million ad campaign against them.” Skaggs proposes:

The solution to this political dysfunction is to empower regular voters as a counterweight to big political money. The Empowering Citizens Act, sponsored by Representatives David Price and Chris Van Hollen, would do precisely that. By matching grass-roots donations from regular voters with public funds, the system would give Congressional candidates an alternative path to victory in which they depend on constituents and voters, instead of deep-pocketed donors seeking political favors. Such a system would give officials the courage to stand up and act in the public interest, not on behalf of the special interests.

The gun lobby certainly has a financial advantage over reform supporters. But campaign finance reform could be the game-changer gun safety reformers need to level the battlefield. Now would be a good time to work on that.