GOP Senate hopefuls adopt a high-risk strategy for November

When Republican Sen. Pat Toomey was in a tight reelection fight in 2016, he made a direct appeal to undecided voters in Pennsylvania: Even Democrats thought highly of him.

“Ed Rendell called Pat Toomey a man of ‘uncommon decency,’” a narrator in one of his ads said of the state’s former Democratic governor. “Tim Kaine praised Pat Toomey’s seriousness, intellect and civility.”

Now the two-term incumbent is among several bipartisan deal-making Republicans retiring from the Senate. They’re members of a moderate wing of the party that recently helped pass a compromise on...