Dressed in a ski jacket to protect her from the morning chill, Sandy Jacobs, an occupational therapist, arrived at a fading, nearly century-old two-family home and knocked on one of the doors.

When no one answered within a few seconds, she knocked on the second one, and suddenly Kimberly Montgomery answered the first door. Ms. Jacobs, a member of the American Federation of Teachers, asked, “Are you going to vote?” Ms. Montgomery responded, “I’ve already voted — for Barack Obama of course.”

Suddenly the adjacent door opened — it was Ms. Montgomery’s sister, Angela. She said she had not voted yet, but she promised she would — also for Mr. Obama.

Theirs were among the 69,176 doors that union leaders said were part of a statewide labor canvass in Wisconsin on Saturday. In labor’s last-minute campaign efforts, canvassers in Eau Claire, Kenosha, La Crosse, Racine, Green Bay and other communities carried the same message: Do not forget to vote, and when you do, cast ballots for President Obama and Tammy Baldwin, the Democratic candidate for Senate.

With labor’s political influence having fallen short in the 2010 elections and with membership declining, unions are hoping that two new strategies will strengthen their efforts this time around.