Democratic leaders have sent tens of millions of dollars to freshman lawmakers’ districts in hope of protecting the party’s newfound majority come November. A new study of December’s omnibus spending package shows that the party in power has resisted pressure to abandon earmarking, at least to the extent of handing lawmakers in tough districts plenty of pet projects they can boast about to voters. Democratic freshmen in the House were among the biggest recipients of earmarked funds, often surpassing much more senior colleagues by millions of dollars. Republicans have made the practice of earmarking a major campaign theme and are...