KCBS_740 SAN FRANCISCO (KCBS) — Tens of thousands of people – many of them in California – are swapping votes across the country to try to help swing the presidential election one way or the other.

There are several apps and websites that connect voters in safely decided states with those in the battleground states. One of them is NeverTrump, started by Silicon Valley entrepreneur Amit Kumar.

Kumar told KCBS that somebody who wants to vote for a third party candidate in Florida, or Ohio for example, will instead vote for Hillary Clinton or Donald Trump – if a Californian agrees to cast a ballot for Jill Stein or Gary Johnson.

“If you’re a Jill Stein supporter in a swing state, we will give you a match for say, a California voter voting for Hillary Clinton, and so, you can trade your vote with them,” Kumar said.

The overwhelming majority are swapping to vote against Donald Trump, though there are some using this system to cast votes against Clinton.

Is it legal? The federal courts say yes, as long as no money changes hands and no contract is signed.

With more than 50,000 votes traded so far, Kumar says, it could flip some close states, from red to blue.

“How much of an impact can it have? Well, as we all know from 2000, the difference was about 500 votes in Florida,” Kumar said.

This works on the honor system, so in the end, there’s no way to be sure your trading partner went through with the deal.