President Obama vs. Donald Trump on the campaign trail

Welcome to Trail Guide, your host through the wilds of the 2016 presidential campaign. It’s Wednesday, Jan. 13, and here’s what we’re talking about:

• Is a battle brewing between President Obama and Donald Trump on the campaign trail?
• Analysis: In State of the Union, Obama aims to have a say in which candidate follows him
• Jeb Bush’s super PAC is spending a lot of money on advertising, but it’s not helping boost his poll numbers
• The Republican debate lineup for this week is set, and Rand Paul and Carly Fiorina did not make the cut
• Paul will skip the so-called “happy hour” debate to campaign in Iowa and New Hampshire