Texas Senator Ted Cruz continues to cling to a slight lead over overall Republican front-runner Donald Trump in the critical, early voting state of Iowa.

A new Fox News poll now shows Cruz registering 27 percent support from likely GOP caucus-goers, good enough for a four-point lead over Trump at 23 percent. Florida Senator Marco Rubio remains in striking distance and third place at 15 percent.

Those numbers represent little change from a month ago, when the same poll found Cruz at 28 percent, compared to 26 and 13 percent for Trump and Rubio, respectively.

Cruz Favorite Among Conservatives

The most recent poll also reveals Cruz's lead grows among would-be voters who describe themselves as "very" conservative. Among that demographic, he bags 40 percent of the vote, nearly doubling Trump who stands at 22 percent.

White evangelical Christians also prefer Cruz to Trump, 33 to 19 percent, and Cruz also leads among likely GOP voters with a college degree, 25 to 18 percent.

In yet another encouraging sign for Cruz, data also reveals Trump may find it difficult to expand his base in Iowa, as roughly one in three voters insist they could "never" see themselves backing the bombastic real estate mogul. That's more than four times as many as say the same thing about Cruz at seven percent.

Overall, 57 percent of Republican caucus-goers in the state insist they feel "betrayed" by party representatives with 66 percent of voters identifying as Cruz supporters expressing such feelings.

GOP Voters Rank "National Security" Top Issue

In all, 36 percent of Iowan GOP voters say national security will be the determining issue in who ultimately gets their vote, compared to 32 percent who say the economy and 12 percent immigration.

Still, even with all the aforementioned variables going in his favor, only 26 percent of caucus-goers believe Cruz will emerge as the party's official nominee, compared to 37 percent for Trump.

Ben Carson (nine percent), Jeb Bush (seven) and Rand Paul (five) are the only other GOP candidates registering at least five percent support in the state. Carson was once polling as many as 14 points ahead of Trump in the state.