One of the most powerful Democrats in Washington is facing a close race

The most powerful Democrat in Congress could face his toughest re-election race yet next year.

Last week, Gravis Insights released a new poll of Minority Leader Harry Reid's (D-Nevada) 2016 race and found him trailing against two lesser-known challengers: Attorney General Adam Laxalt (R) and former Lt. Governor Brian Krolicki (R).

Gravis has a poor track record as a pollster, but its results here are in line with other surveys that have repeatedly suggested Reid could be the most vulnerable Democratic senator up for re-election this cycle.

However, operatives on the both sides of the aisle constantly warn against underestimating Reid, a former boxer who's never afraid to deliver surprising blows in his re-election battles. Indeed, veteran Nevada political reporter Jon Ralston said Reid can never be counted out in a February article in Politico Magazine.

"All other things being equal, Harry Reid cannot win reelection. He is physically and politically battered. He has added more baggage since the miracle of 2010 than has passed through Dulles," Ralston wrote. "But all other things are never equal when it comes to Harry Reid, who specializes in near-death experiences and who always seems down but never is out."

Republicans are most eager to recruit Nevada Gov. Brian Sandoval (R) into the Senate race, but the popular and relatively moderate governor has appeared reluctant to challenge Reid so far. According to Ralston, Reid's most likely foe is state Senate Majority Leader Michael Roberson (R), who was not included in the Gravis poll.

Then-Minority Leader Mitch McConnell (R-Kentucky) also faced a tough re-election race in 2014, and polls similarly indicated he was unpopular in his home state. He ultimately won easily against Kentucky Secretary of State Alison Lundergan Grimes (D) and is now the majority leader.