WESTFIELD, United States: Republican presidential hopeful Donald Trump campaigned for a second straight day with a potential running mate, test-driving Indiana Gov. Mike Pence on Tuesday before the expected announcement of his pick later this week. It could be one of the most important decisions Trump makes on the campaign trail as he seeks to present a competent, steady wingman or woman to US voters after a turbulent primary season during which his provocative rhetoric frustrated many conservatives. He will also be under pressure to name someone with political savvy and policy chops for the battle against the more experienced Hillary Clinton in the November election. Stock in Pence, 57, has soared recently as someone who could provide the provocative billionaire with the steady tone that would neutralize Trump’s combativeness. His deep resume would also counter the candidate’s political inexperience. A handful of others are in the mix, including New Jersey Gov. Chris Christie, a hard-nosed leader of a populous state, who campaigned with Trump in Virginia on Monday. Former House speaker Newt Gingrich, who himself ran for President in 2012, is also on the short list.