As the 2016 presidential cycle looms larger in the minds of political reporters, the “invisible primary” is becoming less and less opaque.

The hawkish casino magnate, notable establishmentarian, and prolific GOP donor Sheldon Adelson is reportedly beginning to turn a favorable eye toward Sen. Marco Rubio (R-FL). According to Politico, Adelson sees Rubio as “the future of the Republican Party.”

“He has also said that Rubio’s Cuban heritage and youth would give the party a strong opportunity to expand its brand and win the White House,” Politico reported.

Adelson might be making a smart bet. According the latest Quinnipiac poll, Rubio now leads the field of Republican candidates as the top choice of GOP primary voters to win the party’s presidential nomination. “The Republican primary field shows Rubio with 15 percent, former Florida Gov. Jeb Bush with 13 percent and Wisconsin Gov. Scott Walker with 11 percent,” the Quinnipiac University poll’s release read. “No other candidate tops 9 percent and 14 percent remain undecided.”

Rubio’s bounce in the polls follows his presidential announcement ten days ago. Although Rubio’s boost in support is apparently more pronounced than those of Sens. Ted Cruz (R-TX) and Rand Paul (R-KY), both of these candidates experienced a similar bounce in polls of GOP voters following their campaign unveilings.

While it may be tempting to write off Rubio’s bounce as a natural outgrowth of the hype that accompanied his announcement, the Florida senator’s performance against Hillary Clinton in this poll is harder to dismiss. Of the seven Republican candidates Quinnipiac tested, Rubio comes closest to besting Clinton in a head-to-head matchup. In this survey, 43 percent of respondents backed Rubio while 45 percent expressed support for Clinton; a finding within this survey’s 2.7 percent margin of error.

Although Rubio is clearly rising in the estimation of the national electorate, Clinton is almost certainly falling. This poll found that Clinton’s personal favorability rating is now underwater, with 46 percent of respondents holding a favorable opinion of her compared to 47 percent who do not. 54 percent said they do not believe Clinton is “honest and trustworthy,” compared to just 38 percent who do. But perhaps the worst finding for this poll from Clinton’s perspective was on the matter of whether she “cares about the needs and problems of people like you.” In this poll, 47 percent said that she does while another 47 percent disagreed. In 2012, exit polls found that Obama beat Romney on this question by an overwhelming 63-point margin.

The news is not, however, all bad for Clinton in this poll. While 53 percent believe a congressional investigation into Clinton’s use of personal email to conduct government affairs while secretary of state is justified, 51 percent also say that investigation is politically motivated. While this sounds contradictory, and it is, this finding is indicative of how deeply the public continues to mistrust Republicans in Congress. What’s more, a slim majority of voters still approve of Clinton’s performance as America’s top diplomat. Finally, a whopping 62 percent of respondents, including 36 percent of self-described Republicans, see Clinton as having “strong leadership qualities.”

While dreary Eeyores on the Republican side of the aisle will contend that the GOP candidates are relatively unknown and there is plenty of time for Democrats to define them in negative terms for the electorate, Clinton might be in an even worse position. The former secretary of state is not making a first impression among voters, but is forcing them to revise their original take on who she is and how she would lead the country. And all of this revision has occurred before Clinton has drawn a serious primary opponent, has subjected herself to an interview with an adversarial figure in the press, or faced a Republican on the debate stage.