11/04/2014 06:16 pm ET Updated Nov 04, 2014

Liberal Group Makes Last-Ditch Push For Potentially Pivotal South Dakota Senate Seat

WASHINGTON -- Democracy for America, a grassroots progressive group, is trying to organize a last-minute push to get out voters on a Native American reservation in South Dakota that the group argues may be key to Democratic control of the U.S. Senate.

Two polling locations in Shannon County, South Dakota, will remain open until 8 p.m. Mountain Time on Tuesday. South Dakota Secretary of State Jason Gant told The Huffington Post that Pine Ridge Precinct 1 and Oglala Precinct 1 opened late this morning and would stay open an additional hour. Under state law, polling locations must be open 12 hours. The two polling sites largely serve members of the Oglala Sioux tribe on the Pine Ridge Reservation.

Democracy for America sent an email Tuesday afternoon noting that the late openings had caused long lines and delays. The group urged its supporters to help with last-minute calls to get out the vote for the state's U.S. Senate race, which pits Democrat Rick Weiland against Republican Mike Rounds and Independent Larry Pressler. While Weiland had seen a surge late in the campaign that put him closer to poll-leader Rounds, a Weiland victory appeared increasingly unlikely late Tuesday.

DFA's email argued that votes for Weiland in those precincts could help determine control of the Senate:

Polling locations in the largest Native American reservation in South Dakota opened LATE this morning, and now people are stuck waiting in extremely long lines. We need to let voters know that some polling locations in the Pine Ridge Reservation will be open until 8 PM Mountain Time tonight to accommodate voters.

Shannon County is also one of 28 jurisdictions in 18 states where the Department of Justice's Civil Rights Division on Tuesday is conducting in-person election monitoring. Gant said it was "just coincidence" that the extended hours were happening in the same county and that the delay was "nothing related to race whatsoever."

The 2.1 million-acre Pine Ridge Reservation has been the focus of "get out the vote" efforts this year, with a number of liberal groups helping provide transportation and other support to assist voters with early voting and with getting to the polls on Election Day.

The extended hours also mean that results will likely be delayed as well.