An effort by liberal groups to pressure Republicans to allow Senate consideration of President Barack Obama’s Supreme Court nominee got off to a modest start Monday as small groups of demonstraters rallied outside lawmakers’ offices around the country. A bigger election-year battle ramped up as both sides brought their viewpoints to television, social media and supporters’ email inboxes. Five days after Obama tabbed federal appeals court Judge Merrick Garland for the vacant seat, about 25 people appeared outside the Columbus, Ohio, office of GOP Sen. Rob Portman, who is backing Republican leaders’ insistence on awaiting the pick of whoever is...