Teacher:In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Teacher: Now, understand the problem? Solve this instance: Rick Santorum suspended his campaign for the Republican presidential nomination Tuesday, leaving the field clear for Mitt Romney as the party's likely choice to challenge President Barack Obama in November. 
  
 FILE - In this April 5, 2012 file photo, Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks in Tunkhannock, Pa. Romney is pouring nearly $3 million into TV ads in Pennsylvania... (Associated Press) 
  
 FILE - In this March 31, 2012 file photo, Republican presidential candidate, former Pennsylvania Sen. Rick Santorum pauses while speaking at the Faith and Freedom Coalition Presidential Kick-Off in Pewaukee,... (Associated Press) 
  
 President Barack Obama walks across the tarmac to greet people upon his arrival at Palm Beach International Airport in West Palm Beach, Fla., Tuesday, April 10, 2012. (AP Photo/Carolyn Kaster) (Associated Press) 
  
 The former Pennsylvania senator made the announcement in his home state, two weeks before the Republican primary vote there. Santorum was trailing Romney in polls in Pennsylvania and had said the state was a must-win to keep his candidacy alive. 
  
 "This race is over for me," Santorum told supporters of his improbable campaign, saying he and his family had made the decision over the weekend after his 3-year-old daughter's latest hospitalization. 
  
 Santorum was a favorite of the most conservative Republican voters, but Romney, the former Massachusetts governor, had accumulated a huge lead in delegates to the party's national convention in August. 
  
 Santorum pointedly made no mention or endorsement of Romney, whom he had derided as an unworthy standard-bearer for the Republicans. 
  
 Romney congratulated Santorum on his campaign, calling him an "able and worthy competitor." 
  
 Romney's conservative credentials are suspect among the conservative Republican base, but Santorum's inability to put together primary election victories in key states _ especially in the industrial Midwest _ appeared to have convinced most voters that Romney's nomination was inevitable. 
  
 Santorum was the only Republican in what started out as a crowded field who was able to create a sustained challenge to Romney, who is making his second run for the nomination. The distaste that conservatives felt for Romney showed itself in a series of runs at his front-runner status by Rep. Michelle Bachmann, Texas Gov. Rick Perry, businessman Herman Cain and former speaker of the House of Representatives Newt Gingrich. 
  
 Gingrich on Tuesday said he would stay in the race until the party's convention. 
  
 Santorum was to have returned to the campaign trail Tuesday after his 3-year-old daughter Bella was released from the hospital. She suffers from a rare genetic condition and was hospitalized Friday as her father began a brief holiday break from campaigning. She was discharged from the hospital Monday night. 
  
 Romney said her latest hospitalization led him and his family to decide against continuing in the race. 
  
 Five states, including Pennsylvania, hold primaries April 24 
  
 President Barack Obama, meanwhile, stepped up his election-year insistence that the wealthy pay a greater share of taxes, renewing his call Tuesday for Congress to raise taxes on millionaires. 
  
 Hoping to draw a sharp contrast with Romney, Obama outlined his support for the so-called "Buffett rule" in Florida. Obama says he wants to revamp the U.S. tax law under which wealthy investors often pay taxes at a lower rate than middle-class wage-earners. 
  
 The push for the Buffett rule is named after billionaire investor Warren Buffett, who famously said it was wrong for him to be paying a lower tax rate than that levied on his secretary. 
  
 Obama has proposed that people earning at least $1 million annually, whether in salary or investments, should pay at least 30 percent of their income in taxes. Many wealthy taxpayers earn investment income, which is taxed at 15 percent, allowing them to pay a smaller percentage of their income in taxes. The top rate for taxpayers with high incomes derived from wages is 35 percent. 
  
 The White House said in a report released ahead of Obama's speech that the tax proposal would restore fairness to the system, pointing to 22,000 households earning more than $1 million annually that paid less than 15 percent of their income in income taxes in 2009. Nearly 1,500 of those households paid no federal income taxes, the report said. 
  
 Obama also was holding three fundraisers in Florida that were expected to raise at least $1.7 million. 
  
 Romney campaign spokeswoman Gail Gitcho said Obama was the "first president in history to openly campaign for re-election on a platform of higher taxes." ||||| GETTYSBURG, Pa. — Rick Santorum announced Tuesday afternoon that he is ending his campaign for the presidency, effectively closing out the GOP primary season and cementing Mitt Romney's status as his party's presumptive nominee. 
  
 The decision to shutter his campaign comes days after Santorum's youngest daughter, Bella, was hospitalized with a chronic and serious medical condition. Santorum's team said last night that Bella had been released from the hospital and Santorum was set to resume his campaign schedule. 
  
 But in Gettysburg today, Santorum said his family had conferred over the weekend and concluded it was time to bring his White House bid to a close. 
  
 "This was a time for prayer and thought, this past weekend, just like it was, frankly, when we decided to get into this race. Karen and I and the kids sat at the kitchen table and talked about our hopes and fears and concerns," Santorum said. 
  
 Declaring that his run had enabled "conservatives to have a voice" in the nominating process, Santorum cast his campaign as the longest of long-shot enterprises. 
  
 "Miracle after miracle, this race was as improbable as any you will ever see for president," he said, insisting that while his candidacy is over, "We are not done fighting." 
  
 "I know a lot of folks are going to write, maybe even those at the White House, game over. But this game is a long, long way from over," Santorum continued. 
  
 By dropping out now, Santorum spared himself the potential embarrassment of a loss to Romney in Pennsylvania's April 24 primary. The Santorum and Romney campaigns were in communication over the weekend, sources in both campaigns said, and those talks intensified Monday. 
  
 Romney and Santorum spoke directly ahead of Santorum's withdrawal, sources said. Santorum also had a conversation with Republican National Committee Chairman Reince Priebus and planned to speak with his top supporters on a conference call later Tuesday. 
  
 Santorum did not endorse Romney in his afternoon remarks. Hogan Gidley, a spokesman for his campaign, said in an MSNBC appearance that Romney had reached out to Santorum to request a meeting about an endorsement. 
  
 In a statement on Santorum's announcement, Romney made no mention of the meeting or a possible endorsement, calling his once-bitter foe an "able and worthy competitor." 
  
 "He has proven himself to be an important voice in our party and in the nation," Romney said. "We both recognize that what is most important is putting the failures of the last three years behind us and setting America back on the path to prosperity." 
  
 Now that Santorum is finished as a candidate, Romney may now turn his attention to the general-election fight with President Barack Obama and the task of uniting a fractured Republican coalition. 
  
 That process was already under way as Santorum's campaign faltered over the past few weeks. After losing a series of big-state nominating contests — most recently Wisconsin on April 3 — Santorum had pinned his hopes for a comeback on his home state. 
  
 But Romney's campaign and super PAC have been pumping millions of dollars into TV ads there and polls have shown Santorum's lead diminishing. If Santorum had lost Pennsylvania — in addition to four other states voting that day where Romney is favored — it would have marked an embarrassing end to an impressive insurgent conservative presidential run. 
  
 Instead, Santorum now has the opportunity — if he wants to take it — to recast himself as a party leader and national conservative spokesman, perhaps reclaiming some of the prestige he lost after his mammoth 2006 reelection defeat. 
  
 (Also on POLITICO: PHOTOS: A look back at Santorum's career) 
  
 Pennsylvania GOP Chairman Rob Gleason, who spoke to Santorum earlier Tuesday, said Pennsylvania Republicans are "proud of the good work that he did as a candidate. He did a great credit to himself and our party." 
  
 And social conservative leader Gary Bauer, the former Family Research Council head who endorsed Santorum's campaign, praised his candidate for an "outstanding campaign." 
  
 "His contribution to the debate has made the GOP stronger, and will contribute to the end of the Obama administration this November," Bauer said. "He and his family have made a wonderful contribution to the future of our country." 
  
 Santorum's departure from the race leaves just Newt Gingrich and Ron Paul, the third- and fourth-placed candidates in the delegate chase, still in the contest as conservative opponents to Romney. Gingrich has acknowledged that it is all but certain Romney will be Obama's opponent in November. 
  
 Both remaining Romney opponents put out statements of their own calling Santorum's surrender a sign that conservatives ought to move in their direction. 
  
 "Dr. Paul is now the last — and real — conservative alternative to Mitt Romney," Paul's campaign said. 
  
 Gingrich, too, emphasized that he's in the race for the long run: "I am committed to staying in this race all the way to Tampa so that the conservative movement has a real choice. We know well that only a conservative can protect life, defend the Constitution, restore jobs and growth and return to a balanced budget." 
  
 This report has been updated. Reid Epstein contributed to this report. 
  
 Read more about: Rick Santorum, 2012 Elections |||||
Student:
Rick Santorum is out. He officially left the GOP race today in Pennsylvania, saying his daughter Bella's most recent scare in the hospital caused him to re-evaluate things. "This race is over for me," he said, adding that he'll continue to fight to help defeat President Obama. He did not, however, mention Mitt Romney in his speech, reports AP. The move helps Santorum avoid a potentially embarrassing home-state loss to Romney on April 24, notes Politico, and allows him to leave the race with an impressive underdog showing. "Against all odds, we won 11 states," he said. "This was a time for prayer and thought, this past weekend, just like it was, frankly, when we decided to get into this race. Karen and I and the kids sat at the kitchen table and talked about our hopes and fears and concerns,” said Santorum. He added later: “Miracle after miracle, this race was as improbable as any you will ever see for president."