WASHINGTON – Moving ahead with one of his most consequential decisions, President Barack Obama has begun informal talks with potential nominees for the Supreme Court. And now he is reaching out to senators who ultimately will control the fight ahead to confirm his nominee.

Obama on Wednesday was to meet with the top Democrat and Republican in the Senate, along with leaders of the Senate Judiciary Committee, as he launches a period of political protocol that comes with each high court nomination. The White House says the point is for Obama to get advice from the senators on how to proceed and even ideas of people to consider, but his goal is also to show bipartisanship, even if the debate to follow is almost sure to have a divided tone.

At the White House, Obama will gather with Senate Majority Leader Harry Reid of Nevada, Senate Minority Leader Mitch McConnell of Kentucky, Judiciary Committee Chairman Patrick Leahy of Vermont and Sen. Jeff Sessions of Alabama, the ranking Republican on the committee...