As noted, seniors are of interest given Ryan’s proposal to revamp Medicare with a system in which the government would give older Americans a fixed sum with which to buy insurance. They moved in Ryan’s favor, from a 28-28 percent favorable-unfavorable view prospectively to 46-28 percent this weekend. Again a sizable number, 26 percent, are undecided; debate over Ryan’s position on Medicare may inform their views.

Younger adults, age 18-39, also moved in Ryan’s favor, but from a more negative view before the announcement, 18-29 percent positive-negative, to a divided one, 34-36 percent.

Ryan also saw a gain among women, a weak group for Romney compared with Obama; favorable views of the choice rose from 19 percent of women last week to 37 percent this weekend. Among men they went from 27 percent previously to a similar 38 percent after the announcement was made.