Test running-mate judgments

Mike Pence and his wife Karen arrive in Zionsville, Ind., for a Welcome Home Rally last Saturday. (AP Photo/Darron Cummings)

More than 128 million U.S. voters cast ballots for president in 2012.

But it only takes one person to pick a running mate on a White House ticket.

That critical choice gives voters a chance to gauge a presidential nominee’s judgment — and a vice presidential nominee’s suitability for the office.

So as Americans consider whether they should vote for Donald Trump, who officially won the Republican presidential nomination Tuesday night, they must also consider his decision to put Indiana Gov. Mike Pence on the GOP ticket.

They should remember, too, that vice presidents can suddenly get promoted to the top job by circumstance.

Of course, who’s No. 1 on a ticket, not who’s No. 2, invariably is the decisive factor in who wins a presidential election. That rightly puts the primary focus on Hillary Clinton and Mr. Trump, who was praised in nominating speeches Tuesday by, among others, South Carolina Lt. Gov. Henry McMaster.

Then again, 14 vice presidents have become president. Eight of those initially did so because a president died, and one because a president resigned. Five other vice presidents were ultimately elected to the presidency without first getting the position due to the death of a president.

Yes, Donald Trump and Hillary Clinton are apparently in good health.

However, Mr. Trump turned 70 last month, and Mrs. Clinton will turn 69 in October.

And even if our next president were much younger than that, a vice president must always be ready to quickly take over the nation’s highest elective office.

As for Mr. Pence, he’s made a significant mark within the political realm, having served six terms in the U.S. House before winning Indiana’s governorship in 2012. Still, many Americans don’t know much about him.

That makes Gov. Pence’s acceptance speech tonight at the Republican convention in Cleveland a timely learning opportunity for voters as they assess him — and by obvious linkage, Mr. Trump.

The same principle will apply at the Democratic convention in Philadelphia next week when Mrs. Clinton’s running mate, as yet unnamed and also possibly relatively unknown, makes his — or her — acceptance speech.

Then after hearing more from all of the candidates (and their supporters and detractors) over the next 3½ months, the voters, not the pundits or the polls, will decide who will be our next president — and vice president.

So if you want to make a better informed decision, check out those running mates as they make their pitches to the nation tonight and next week.

After all, one of them will be sworn in as vice president six months from today.

One of them might even become president some day.