By Ginger Gibson and Emily Stephenson
WASHINGTON (Reuters) - Republican presidential hopeful Ted Cruz is leaning on new sources of cash as he prepares for a long primary fight against front-runner Donald Trump, with new campaign finance filings showing the expense of competing against a billionaire adept at grabbing headlines.
Cruz's more traditional campaign has struggled to compete with Trump. The U.S. senator from Texas poured money into advertising, staff and calls to voters, spending $5.6 million more in February than he raised as he tried to outmaneuver Trump, according to campaign finance records made public on Sunday.
But the effort had a limited impact as Trump took a commanding lead in the delegate count for the Republican nomination while spending a little more than half what Cruz did. The real estate mogul has loaned his campaign more than $24 million since he entered the race for the White House.
Now, with establishment Republican rivals Jeb Bush and Marco Rubio out of the race, Cruz is trying to win votes and rake in money by arguing the party should unite behind him if it hopes to defeat Trump.
It's a tough proposition for a conservative candidate who has long rankled the establishment wing of his party, including by leading a fight over President Barack Obama's signature healthcare law that led to a 16-day shutdown of the federal government.
Cruz now hopes to convince his party that he, not Ohio Governor John Kasich, the other Republican remaining in the race, is best poised to defeat Trump and go on to the Nov. 8 presidential election.
In a sign of Cruz's warming ties with establishment Republicans, South Carolina Senator Lindsey Graham, who has been a vocal critic of Cruz, plans on Monday to hold a fundraiser for the senator from Texas.
Charles Foster, a Houston immigration attorney who backed Bush until he left the race in February, said Friday he is urging establishment Republicans to line up behind Cruz.
"My pitch to them simplistically is that Trump is an existential threat. He'd be a total disaster," Foster said.
"The only person that has a real chance," he added, "particularly within the Republican primary base, which is conservative, far more conservative than Kasich, is Ted."
Trump has a substantial lead in the Republican White House race, though he remains far short of the 1,237 delegates needed to clinch the nomination. It is unclear whether he will hit that number before the July convention in Cleveland, but it would also be difficult for either Cruz or Kasich to catch him.
Cruz could pick up delegates in Utah, which holds its caucus on Tuesday, and all of the candidates are expected to compete hard in Wisconsin on April 5. But so far, efforts to stop the Trump juggernaut have made little impression on voters.
In February, Cruz raised $11.9 million and spent $17.5 million, leaving his campaign with $8 million when he woke up on Super Tuesday. And despite the heavy spending, Cruz won just one state that voted in February and three on the March 1 Super Tuesday primaries.
In addition to self-funding his campaign, Trump has the advantage of running an operation that leans heavily on free media exposure. In February, Trump, raised $9.2 million, including a $6.9 million loan he gave his own campaign, and spent $9.5 million.
Kasich raised $3.4 million in February and spent $3.6 million.
About half of Cruz's spending, or more than $8.7 million, was on advertising. Cruz also allotted $2.6 million to traditional campaign tactics like printing mailers, postage stamps and phone calls to voters.
Cruz did spend a bit less than Trump on staff, recording $342,525 in payroll costs in February to Trump's $370,973.
Jeff Roe, Cruz’s campaign manager, said on Twitter on Sunday the campaign has enough cash to continue competing through June 7, the last Republican primary day when hundreds of delegates are up for grabs.
(Additional reporting by Grant Smith; Editing by Caren Bohan and Mary Milliken)