Republicans are hearing a lot about how they need to abandon their principles on such issues as same-sex marriage and abortion if they want to win elections. But the GOP's problem is not that it is too socially conservative; it is that Republicans are seen as defenders of the rich and powerful instead of the poor and vulnerable.If Republicans want to change that impression, there is a simple solution: Be more like Pope Francis -- defender of the family, the unborn and the poor.Mitt Romney did not lose the presidency because he opposed same-sex marriage. He lost because he dismissed 47 percent of the country as a bunch of moochers. He lost because he was seen as out of touch with Americans who are struggling to keep their heads above water.An Economist/YouGov poll last April tells the story: 35 percent of Americans said they believed that Romney cares about the poor, and 38 percent said Romney "cares about people like me." You can't win the presidency when two-thirds of the country thinks you don't care about their struggles.Beating a retreat on marriage and abortion would do nothing to solve that problem. To the contrary, it would cause a rift in the Republican Party and alienate the GOP's most dependable voters: Christian conservatives, for whom these are non-negotiable moral issues.But a conservative campaign against poverty could enlist and energize the same voters and broaden the party's appeal beyond its conservative base.One lesson from the Holy Father is that saying the right things about poverty is not enough. You have to show up.The Associated Press reports that residents of one of Buenos Aires's poorest neighborhoods, Villa 21-24, call Francis their "papa villero," or slum pope. They recall how, as Cardinal Jorge Mario Bergoglio, he "would arrive on a bus to their little chapel; how he sponsored marathons and carpentry classes, consoled single mothers and washed the feet of recovering drug addicts; how he became one of them."If Republicans want to convince Americans that they care, they need to emulate Francis and start showing up in the barrios and the inner cities.It's not enough for Republicans to vote for school choice; they need to spend time with students struggling in failing schools. It's not enough to rail against dependency; they need to spend time helping those trapped in dependency get the skills to get off public assistance. It's not enough to complain about President Barack Obama's class-warfare rhetoric; they need to spend time fighting for the vulnerable.They don't have to abandon their principles. As a cardinal, Bergoglio urged the faithful to "defend the unborn against abortion even if they persecute you, calumniate you, set traps for you, take you to court or kill you." But also he insisted that "no child should be deprived of the right to be born, the right to be fed, the right to go to school."Notice that he did not stop at the right to be born. Neither should Republicans. The GOP needs to put as much emphasis on ensuring that children are fed and educated as it does on their fundamental right to life.Now is the perfect moment for conservatives to offer innovative, free-market alternatives to the permanent welfare state.Spending on social-welfare programs for the poor has grown by 50 percent since 2007, yet under Obama, more than 2.6 million Americans have slipped out of the middle class and below the poverty line. If Republicans want to be seen as a more welcoming party, the best way to prove it is by welcoming the poor and championing the vulnerable.At his installation Mass on March 19, Francis called on political leaders to "embrace with tender affection the whole of humanity, especially the poorest, the weakest, the least important ... the hungry, the thirsty, the stranger, the naked, the sick, and those in prison."That is a call Republicans should answer.Marc A. Thiessen is a fellow with the American Enterprise Institute and writes a weekly online column for the Post.