Democrats: 63 percent say they are 100 percent sure they would vote for Trump over Clinton.

Republicans: 39 percent say they are 100 percent sure they would vote for Clinton over Trump.

Agree completely: 25 percent.

Agree somewhat: 14 percent.

Agree completely: 21 percent.

Agree somewhat: 11 percent.

Nearly 20 percent of Democrats would leave the party and vote for Republican Donald Trump in a match-up against Hillary Clinton, according to a new poll.The survey of 916 likely voters by the Mercury Analytics research firm in Washington found that only 14 percent of Republicans would cross party lines and vote for Clinton."The challenge to Hillary — if Trump is the nominee and pivots to the center in the general election as a problem-solving, independent minded, successful 'get it done' businessman — is that Democrats will no longer be able to count on his personality and outrageous soundbites to disqualify him in the voters' minds," said Ron Howard, Mercury Analytics CEO.The survey was conducted between Wednesday and Friday and has a margin of error of 3.5 percent.Here are the key results among crossover voters:Are you 100 percent sure that you vote for the candidate of the other party?In other results, the poll tested response among the Democrats to Trump's first campaign spot, which was unveiled on Monday:Do you agree that Trump's ad raised some good points?Does Trump’s ad represent how you feel?"We expected Trump’s first campaign spot to strongly appeal to Republican Trump supporters, with little impact — or, in fact, negative impact — on Democratic or independent voters," Howard said. "However, what we see is that among a segment of Democratic and independent voters who don’t like the 'messenger' of Trump, the issues he is raising — immigration, terrorism — are real concerns they share."