MADISON, Wis. — A new poll shows independent voters breaking toward Republican U.S. Senator Ron Johnson over his challenger, Mandela Barnes  — the state’s  Democratic lieutenant governor. Johnson broke broke the 50% threshold among all likely voters in the survey by the American Association of Retired Persons. The poll gave Johnson a 10-point advantage among independent voters and 5 points overall. Among independents, the poll increased Johnson’s lead but by a narrower margin than a Marquette Poll pulse-beat read of voters two weeks earlier. Both the AARP and Marquette polls show the critical role of independent in the race. The AARP margins:

All likely voters: Johnson 51%, Barnes 46%.

Among Democrats: Barnes 96%, Johnson 2%.

Among Republicans: Johnson 97%, Barnes 2%.

Among independents: Johnson 53%, Barnes 43%.