Latest victims of a volatile GOP race

Sen. Rand Paul of Kentucky and former senator Rick Santorum of Pennsylvania both suspended their 2016 presidential bids Wednesday, victims of a raucous and volatile Republican race in which both struggled to gain traction.

The two joined former Arkansas governor Mike Huckabee in deciding to quit the GOP race this week after disappointing finishes in Monday's Iowa caucuses, which were won by Sen. Ted Cruz of Texas.

Santorum was the runner-up to Mitt Romney during his first presidential bid in 2012, but he faced stiff competition this time for the support of religious conservatives who formed his base then. He formally announced his decision Wednesday evening on Fox News Channel and endorsed Sen. Marco Rubio (Florida) as his preferred Republican nominee, calling Rubio a "tremendously gifted young man."

"He is just the new generation and someone that can bring this country together - not just moderates and conservatives but young and old," Santorum said.

For his part, Paul was unable to expand the libertarian base that his father, Ron Paul, had built into a powerful national coalition.

Paul came under sharp attack from Cruz and others for advocating a non-interventionist foreign policy at a time when many Republicans want stronger military action against the Islamic State.

"It's been an incredible honor to run a principled campaign for the White House," Paul said in a statement. "Today, I will end where I began, ready and willing to fight for the cause of Liberty."

Four years ago, Santorum vaulted from relative obscurity - and a crushing reelection loss in his home state - to win Iowa and 10 other states, only to fade into obscurity again after Romney clinched the GOP nomination.

Santorum looked to build on his winning 2012 approach, making nearly 300 stops and visiting each of Iowa's 99 counties over the course of his latest campaign. But in the caucuses earlier this week, he received fewer votes than any candidate except former Virginia governor Jim Gilmore, who did not actively campaign in the state at all.

Santorum was one of a wave of deeply conservative contenders who believed that after losing two straight presidential elections behind more moderate nominees, GOP voters would turn to a candidate unflinching in ideology who can excite the party's base.

But Ben Carson, Cruz and others occupied the political space that Santorum hoped to again call his own, drawing fervent backing from Christian activists, foreign-policy hawks and populist conservatives.

This time, Santorum's campaign also lacked many of the advantages that had helped fuel his 2012 insurgency - including most of the consultants who engineered it, who went to work for rival campaigns.

Santorum has for decades put his large family, including severely disabled daughter Bella, at the heart of his political life. At his campaign launch this spring near Pittsburgh, he appeared onstage alongside his wife, Karen, and most of their seven children.

He drew notice for speaking passionately about the need for the Republican Party to address the economic concerns of blue-collar workers. He called for an increase in the minimum wage and criticized his party for focusing more on the needs of small-business owners than on issues affecting the people those businesses employ.

"How are we going to win if 90 percent of Americans don't think we care at all?" he asked at a fall debate.

He spent months traveling to each of Iowa's 99 counties. It wasn't enough: His support stayed mired in the low single digits in the state in 2015 and kept him off the main debate stage in the run-up to the first votes of the primary season.

In his closing remarks at his final debate in Iowa last month, Santorum made one last plea to Iowans, pointing to the 700 speeches and town-hall stops he had made in the state over the course of both of his presidential campaigns.

"Here's what I'm asking you to do," he said. "You're good people. You know good leaders. Lead. Pick the right person, not what the polls say. . . . Pick the leader you know is best for this country."

Paul, a first-time candidate for national office, found it tough to persuade supporters of his father - a former congressman from Texas who twice sought the Republican presidential nomination - to back him with enthusiasm.

Although popular among libertarians, purists questioned whether Paul was too mainstream.

The 53-year-old ophthalmologist was elected to the Senate in 2010 as part of the GOP's tea party contingent. He will return to his work in the chamber and to his Senate reelection campaign, where he remains a top target of Democrats as they try to retake the majority this year.

In his statement, Paul expressed confidence that his campaign, while unsuccessful, offered Republicans an alternative by giving attention to issues he thinks are crucial to attracting minorities and young people to the party.

"Across the country thousands upon thousands of young people flocked to our message of limited government, privacy, criminal justice reform and a reasonable foreign policy," he said.

Paul's method of campaigning echoed that of his father. He favored small gatherings where he could make lengthy speeches, and preferred orations that cited 18th century French political philosopher Montesquieu. While he was accessible, he did not relish banter with reporters or the glad-handing demands of the campaign.

But his ambitions were grand. Two years ago, he became the first Republican to assemble a network in all 50 states as a precursor to a presidential run - a sign that he was looking to build a campaign that wasn't as ad hoc as his father's.

Magazine covers proclaimed Paul to be one of the party's brightest and most interesting voices - a hemp-wearing, curly-haired maverick who could, in his words, spread the Republican message to "voters with tattoos and without tattoos."