Texas Sen. Ted Cruz is now only three points behind Republican presidential front-runner Donald Trump nationally, which is a statistical tie, a new Fox News poll shows. The number is within the poll's five-point margin of error, according to Newsmax.

The national poll of likely Republican primary voters showed Trump with 41 percent support, Cruz with 38 percent, and Ohio Gov. John Kasich, with 17 percent.

The poll was conducted March 20-22 and had 388 Republican primary voters as respondents.

Ironically, despite his poor poll rating, Kasich has the best chance of beating expected Democratic nominee Hillary Clinton in a hypothetical head-to-head matchup, according to the same Fox News poll. Kasich only hope at getting the GOP nomination would be in a contested convention.

The poll shows Clinton beating Trump, 49 percent to 38 percent, if the election was held today.

But Clinton would lose to Kasich, 40 percent to 51 percent, and to Cruz, 44 percent to 47 percent.

That portion of the poll, also taken March 20-22, had 1,016 registered voters as respondents and has a margin of error of plus-or-minus 3 percent.

Earlier polls conducted in March also showed basically the same results—Cruz tying or beating Clinton in head-to-head matchups while Trump would lose to her. The polls were conducted by Quinnipiac, CBS/New York Times, CNN/ORC, and NBC News/Wall Street Journal.

Only a Bloomberg poll conducted in recent days showed Clinton winning over Cruz by nine points, which is above the 3.4 percent margin of error.

All head-to-head polls between Trump and Clinton taken during at least part of March show Trump losing to Clinton between five and 18 points, and all outside the margin of error.

Meanwhile, former GOP presidential candidate Jeb Bush endorsed Cruz for the Republican presidential nomination on Wednesday, saying the U.S. senator from Texas represents the party's best chance of winning the White House, the Gospel Herald reported.

In a statement, the former Florida governor called Cruz a consistent, principled conservative who has demonstrated an ability to appeal to voters and win primary contests.

"Washington is broken, and the only way Republicans can hope to win back the White House and put our nation on a better path is to support a nominee who can articulate how conservative policies will help people rise up and reach their full potential," Bush said.