Add the nation's Latino voters to those eager to help elect Hillary Clinton president, according to a new poll sizing up the 2016 field and how immigration reform alters attitudes toward the GOP field.

The latest Latino Decisions poll released Monday finds that Clinton, the former secretary of state, is buoyed by a 73-percent approval rating among Hispanics who have voted in the last two elections and would crush her nearest Republican challenger, U.S. Sen. Marco Rubio of Florida, by more than two to one, 66 percent to 28 percent, in 2016.

And if she decides not to run, Vice President Joe Biden would do well, too, beating Rubio 60 percent to 28 percent, said Matt Barreto, associate professor at the University of Washington and the head of Latino Decisions.

With the Latino vote expected to reach 12.5 million in the next presidential election, the GOP is desperate to win back the 40 percent who supported former President George W. Bush but rejected Mitt Romney in 2012. Those who switched to Obama in 2012 more than provided the Democrat with his margin of victory.

Barreto, who is polling for the pro-immigration group America's Voice, said that how the likely Republican presidential hopefuls handle immigration reform could change the outcome of the election.

Based on his new data, only candidates who appear as leaders on the issue can get above the 40 percent margin of Latino support needed to beat a Democrat. If the eventual GOP nominee is against immigration reform, Barreto said the Democratic challenger could "eclipse 80 percent" of the Latino vote, even more than the 75 percent Obama won in 2012.

"Do we think the 40 percent is achievable? Absolutely," said Barreto.

For example if Rubio continues to push for an eventual immigration reform victory in Congress, some 54 percent of Latino voters would be inclined to vote for him. A similar supportive stance by Rep. Paul Ryan or former Florida Gov. Jeb Bush would also push their Latino vote above the 42 percent threshold considered the baseline for winning the presidency.

Vice presidential candidates also matter, said Barreto. But not always positively.

Consider Republican Sen. Ted Cruz and San Antonio, Texas, Democratic Mayor Julian Castro. Adding Cruz would hurt the Republican ticket, while making Castro the vice presidential nominee would significantly boost the Democratic chances.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at