A new CNN/ORC national poll shows Donald Trump and Hillary Clinton maintain comfortable leads in their respective battles to secure 2016 presidential nominations. Despite calls from Republican leaders to replace Trump as the GOP's probable nominee, Republican voters have shown little interest in doing so.

With the Republican field now whittled down to just three candidates, the poll finds Trump leads the pack with 47 percent of the vote, compared to 31 percent for Texas Sen. Ted Cruz and 17 percent for Ohio Gov. John Kasich.

On the democratic side, Clinton leads Vermont Sen. Bernie Sanders 51 percent to 44 percent.

GOP Voters Excited About Trump

The outspoken Trump also stands atop the Republican field in terms of enthusiasm, with 40 percent of all GOP voters saying they are enthused by his candidacy. Only 28 percent of voters admitted to similar feelings when it comes to Cruz and 19 percent said they feel the same about Kasich.

Trump continues to hold widespread appeal with many GOP voters despite an anti-Trump movement by 2012 Republican nominee Mitt Romney, who has urged party voters to coalesce around whichever GOP candidate stands the best chance of beating the party front-runner in their home state.

Romney's comments are widely viewed as an attempt to keep Trump from amassing the 1,237 delegates needed to secure the nomination, paving the way for a brokered convention when party leaders convene in July.

Meanwhile, the CNN poll finds 6 in 10 GOP voters feel that if no candidate wins a majority of delegates votes should go to the candidate who had the most support through election season. Only 35 percent of voters said they want to see another Republican run as a third party candidate if Trump bags the nomination.

All the back and forth has left just 8 percent of Republican voters feeling the party stands united.

Many Voters Expect Democrats to Unite for General Election

When it comes to the Democrats, 44 percent of voters admit the party now feels fractured, but they are convinced it will unite by November's general election.

As it is, 4 in 10 Democratic voters revealed they would be enthusiastic if the liberal-minded Sen. Sanders won the nomination, compared to 34 percent who feel the same way about the former first lady. In addition, 72 percent of Sanders' supporters said they are enthusiastic about his campaign, compared to 55 percent of Clinton voters.

When it comes to potential general election match-ups, both Clinton and Sanders easily top Trump by an average of 16 points. Sanders also tops Cruz by 13 points and Kasich by 6, while Clinton runs even with Cruz and trails Kasich by 6 points.

Voters in Arizona and Utah take to the polls on March 22. Polls show Trump riding the endorsements of immigration hardliners Sheriff Joe Arpaio and former Gov. Jan Brewer to a lead in the border state of Arizona, but he lags behind Cruz in Utah.