ABC News' Michael Falcone, Shushannah Walshe and Arlette Saenz report:

It was the perfect storm. Rick Santorum's decision to cut short his quest for the Republican presidential nomination on Tuesday came after an intense weekend of thought, prayer and conference calls.

According to top sources in the campaign, the former Pennsylvania senator did not reach his decision until late Monday night after a series of conversations with his family and closest aides. His choice to end his bid exactly two weeks to the day before the April 24 Pennsylvania primary came down two major considerations:

First, the Santorum campaign came to terms with the fact that Texas was never going to become a winner-take-all primary, likely denying them a huge treasure chest of more than 150 delegates they hoped would help narrow the gap with Romney on the delegate scoreboard.

Second, Newt Gingrich showed no signs of exiting the race completely any time soon, the Santorum team concluded. They felt that they needed Gingrich's endorsement and a large portion of his delegates to catch up to Romney.

"Rick is smart, he's level headed," Santorum's national communications director Hogan Gidley said in an interview with ABC News. He said that his candidate ultimately reached the conclusion: "If there's no path, if there aren't the delegates, then there's no reason to keep going."

Gidley said that this realization combined with a prayerful Easter weekend and the hospitalization of Santorum's three-year-old daughter, Bella, all led Santorum to step in front of a television cameras in Gettysburg, Pa. Tuesday afternoon and announce that "this presidential race for us is over."

Santorum's decision, however, was not meant to be an escape route to avoid a potentially humiliating loss in Pennsylvania six years after he failed to win re-election to a U.S. Senate seat there, multiple aides said.

"One thing we did feel, we felt pretty darn confident about winning Pennsylvania," said the campaign's chief strategist John Brabender. "We didn't have the money to play in multiple battles…we just couldn't compete in Delaware, Connecticut, and New York at the same time as Pennsylvania."

Brabender said the campaign had television commercials ready to go and county coordinators ready to be deployed. But the Romney campaign was ready too. They were poised to launch an all-out air war against Santorum, having reserved more than $2.2 million of airtime on television stations across the state starting this week.

"If there was a scenario where winning Pennsylvania would have lofted us to winning the nomination, we would have done it," Brabender said. "But it wasn't realistic. Even winning Pennsylvania wouldn't make a difference. We didn't want to do it out of ego; we wanted to do it to beat Barack Obama."

Gidley emphasized that dropping out before the primary was not a choice borne out of fear, "Rick lost Pennsylvania before. It didn't crush him then, it wouldn't crush him now."

But, in the end, the decision did not come easily, and family matters loomed large.

"I told Rick whatever decision he makes he is a father first," another top aide, who requested anonymity in order to discuss Santorum's deliberations candidly, said. "As tough as it was, he reflected on the fact he is a father first and this was the right decision for his family."

The aide added, "At the moment it's never easy to do, you pray about it, agonize about it, but at the end of the day it was the right thing for himself and his family."

Gidley said that "for the most part," members of the tight-knit campaign team agreed with Santorum's decision to exit the race, but there were at least a few voices of dissent.

"In every campaign there is a certain level of fight left," Gidley said. "A lot of the time people just don't want to close up shop, people don't want to end the campaign."

But Brabender said that when it came to Santorum's most trusted inner-circle of advisers, they all felt they had "looked at everything."

"He and Karen were pretty resolute that it was the right thing to do. It was the same way this morning," Brabender added, noting that he had a conversation with Mitt Romney's campaign manager, Matt Rhoades, last night to inform him of the suspension.

Santorum told Romney of his decision by telephone Tuesday morning and he and the two rivals agreed to meet in the near future about a possible endorsement. (Santorum avoided mentioning Romney during his speech in Pennsylvania.)

"They had a conversation," Brabender said. "They will have a meeting down the road. I would imagine a national endorsement would come up at that time. Clearly the goal is to beat Barack Obama and anything Rick can do to facilitate that, Rick will do."

Tuesday's speech represented a full-circle moment for the presidential hopeful. He delivered his remarks from the Thaddeus Stevens conference room at the Gettysburg Hotel - across the hall from the Grand Ballroom where he spent the Illinois primary night exactly three weeks ago.

In an e-mail to Santorum's traveling press corps just before the former senator began speaking Tuesday afternoon, press secretary Alice Stewart, a veteran of Michele Bachmann's presidential campaign who switched to Santorum's, said that just minutes earlier the candidate held a conference call with the entire staff to inform them of his decision. Santorum's wife Karen also joined the call and she thanked everyone from the bottom of her heart for all their hard work, Stewart said.

"He came to this decision to enter the race with much prayer," Gidley said. "I think he came to the conclusion that he needed to suspend the campaign with the same amount of God-led clarity."