For both parties, the 2016 election has laid bare voters’ frustration with Washington and the influence of big money in the political system.

The death of Supreme Court Justice Antonin Scalia and the subject of who will replace him also are major topics.

Rubio’s stumble re-energized some of his rivals as the race heads to the South and reignited questions about whether the 44-year-old first-term senator has the experience to be president.