Donald Trump. AP Photo/Andrew Harnik Former Secretary of State Hillary Clinton bested Donald Trump in a new slew of hypothetical head-to-head matchups between the two presidential candidates.

Several surveys released over the past few days have shown Clinton regaining a commanding lead over Trump in a potential head-to-head matchup, a scenario that appears increasingly likely as both candidates inch closer to clinching their respective parties' nominations.

A Fox News poll released on Wednesday showed Clinton with an 11-point lead over Trump, while a CBS/New York Times poll published earlier this week found Clinton with a 10-point lead over Trump. A Bloomberg survey on Wednesday put the gap even wider, with Clinton leading Trump by 18 points.

Of the seven major national polls conducted this month and recognized by RealClearPolitics, the closest Trump came to victory in a hypothetical race was in a Quinnipiac University poll. That survey, released last week, found the real-estate magnate trailing Clinton by six points.

This month's polls represent a somewhat notable shift from February, when some showed Trump and Clinton in a virtual dead heat. One Quinnipiac University poll conducted in early February displayed Trump within two points, while a USA Today/Suffolk University poll conducted around the same time had Trump ahead by two points.

Many polling experts caution against reading too much into head-to-head polls before candidates clinch the nomination, as perceptions of candidates can change as rivals are eliminated and the actual general-election campaign moves into full swing.

Still, Republicans have increasingly made the case over the past few weeks that nominating Trump would be devastating for Republican candidates up and down the ballot.

Speaking to reporters after an event in Manhattan on Wednesday, Texas Sen. Ted Cruz embraced his role as the Republican candidate most poised to beat Trump. He said that nominating the real-estate magnate "hands the general election to Hillary Clinton," while touting recent high-profile endorsements from an array of Republican establishment leaders.

Cruz said:

What we have seen, and we see this every day, is Republicans uniting. In the last 10 days, our campaign has been endorsed by Jeb Bush, by Mitt Romney, by [Utah Sen.] Mike Lee, and [conservative radio host] Mark Levin. That's about as broad a spectrum of the Republican Party, across the ideological spectrum.

Sen. Lindsey Graham, who has endorsed Cruz despite his reservations about the candidate, said on Thursday that Ohio Gov. John Kasich would be a better president than Cruz and had the best shot at winning in the general election. The recent surveys, in fact, have shown Kasich ahead of Clinton in theoretical matchups.

But Graham said that Cruz was the only person who could win the Republican primary and the general election, as Kasich cannot amass enough delegates to win the nomination before this summer's Republican National Convention.

"I think John Kasich would be the best nominee, but he doesn't have a chance," Graham said during a Thursday "Morning Joe" appearance.

He added: "We can lose in 2016, and we probably will. Trump gets wiped out. Ted makes it competitive. I don't know if he can beat her or not, but at least we got a fighting chance."