Kentucky’s U.S. Senate candidates have brought potential presidential contenders to help boost voter turnout in the final week of one of the country’s most closely watched races.

U.S. Sen. Elizabeth Warren campaigned with Democratic candidate Alison Lundergan Grimes Tuesday and Hillary Clinton campaigned with her Saturday in Lexington, Ky., and northern Kentucky. Louisiana Gov. Bobby Jindal appeared with Senate Minority Leader Mitch McConnell Wednesday.

With Democrats and Republicans fighting for Senate control, the three politicians have swooped into key battleground contests in states like Arkansas and North Carolina.

Kentucky has been a magnet for big-name politicians as McConnell is trying to become the Senate majority leader while facing his arguably toughest re-election campaign.

Warren and Clinton are making their second trips to Kentucky for Grimes.

Former Republican presidential nominee Mitt Romney and former Secretary of State Condoleezza Rice have traveled to Kentucky to support McConnell. Former Arkansas Gov. Mike Huckabee – another potential 2016 GOP hopeful – stumped for McConnell in Louisville, Ky., last weekend.

Despite the high-profile help, McConnell’s campaign has stuck to one message: connecting Grimes to President Barack Obama, who is deeply unpopular in the state. McConnell’s campaign continued that theme Monday as the senator campaigned in eastern Kentucky with country music star Lee Greenwood.

“Alison Lundergan Grimes has run a race heavily reliant on help from left-wing elites, so it’s not surprising that she would hand the mic to an anti-coal liberal to deliver her closing argument,” said McConnell adviser John Ashbrook.

FRANKFORT, Ky. (AP)