WASHINGTON, May 5 (UPI) -- Even though Donald Trump has the 2016 Republican nomination all but locked up, the party's closest member to the presidency said Thursday he can't yet put himself in the billionaire's corner.
"I'm just not ready to do that at this point," he told CNN. "I'm not there right now."
The Wisconsin congressman has previously said he will support whoever emerged victorious from the party's presidential race -- but, at the same time, he has often clashed with Trump over ideologies or rhetoric from the outspoken real estate magnate.
"I don't want to underplay what he accomplished, [but] we hope that our nominee aspires to be Lincoln and Reaganesque," Ryan said Thursday, adding that he prefers a candidate who "appeals to a vast majority of Americans."
If Trump ultimately receives the official Republican nomination, which appears inevitable, it's likely that Ryan would at some point back his bid for the White House. However, his reluctance to immediately fall in-line with Trump's campaign in the absence of any remaining GOP challengers is a stark indicator of the divisiveness that currently exists within the conservative party -- a dynamic that's most certainly not lost on Ryan.
"I think what is required is that we unify this party," he said. "I think the bulk of the burden on unifying the party will have to come from our presumptive nominee."
Trump's path to the GOP nomination was finally cleared on Wednesday when Ohio Gov. John Kasich became the last contender to drop out of the race. Kasich's exit came hours after a similar departure by Texas Sen. Ted Cruz after Trump easily won the Indiana primary and represented the party's only chance to take back the White House in November.
Ryan indicated Thursday that he may eventually come around regarding Trump's campaign, saying he hopes he will want to endorse the official GOP nominee at some point, but only after all the burning questions are extinguished.
"I think conservatives want to know: Does he share our values and our principles?" He asked. "There are lots of questions that conservatives, I think, are going to want answers to, myself included."
"Things will be fine," Trump said Wednesday. "I'm not running for president to make things unstable for the country."
Ryan's stance, though, is more reluctant than that of other Republican leaders -- including Senate majority leader Mitch McConnell and former candidates Ben Carson, Scott Walker, Bobby Jindal and Chris Christie -- who endorsed Trump not long after Tuesday's win in Indiana.
An unconventional and highly controversial candidate, though, Trump has proven to be anything but a harmonious choice among the party elite. With hopes to deny Trump the nod, some have encouraged what would amount to a political revolt at the Republican National Convention this summer in Cleveland, where Ryan will serve as chairman.
Additionally, some Trump opponents pitched a scenario earlier this year that would have Ryan effectively "drafted" into the race -- a prospect the house speaker rejected multiple times. In fact, he expressly stated that he wouldn't enter the race under any circumstance -- including, apparently, one in which Trump is in the GOP driver's seat.
"Count me out," he stated bluntly last month. "I should not be considered. Period."
"I understand that Americans are angry and frustrated. But we do not need someone in the Oval Office who mirrors and inflames our anger and frustration," the younger Bush said in February.
The party's candidate in 2012, Mitt Romney, has also refrained from endorsing Trump. Ryan was Romney's running mate four years ago.
Since his election to the speaker post in October, Ryan has been viewed as a great unifying force for the Republican Party. As House speaker, he is one of Congress' top leaders -- and at No. 2 in the presidential line of succession, after the vice president, he is presently the GOP's closest member to physically occupying the Oval Office.
Trump, though, is clearly working to rehabilitate his controversial image, which stems from numerous outspoken opinions made in the past -- some of which were viewed by critics as derogatory, sexist and even racist. The businessman, however, has always refuted such accusations.
"The best taco bowls are made in Trump Tower Grill," he said in a light-hearted tweet Thursday. "I love Hispanics!"