LAS VEGAS (AP) — Former Nevada Sen. Harry Reid appeared in a campaign advertisement Friday for Clark County Commission Chair Steve Sisolak, providing a big boost to Sisolak a day before Democratic voters start casting ballots in his contentious primary for Nevada governor with fellow Clark County Commission member Chris Giunchigliani.

Sisolak's campaign released a 15-second ad where Reid called President Donald Trump a bully and said as governor, Sisolak "will not allow anyone, including Donald Trump, to push him around."

Reid then said of Sisolak: "He will be one of the best governors we've ever had."

Reid had previously endorsed Sisolak but his appearance in the ad, which began airing Friday in the Las Vegas and Reno areas, provides a big, visible endorsement for the candidate. Sisolak has also picked up an endorsement from Nevada Democratic Rep. Dina Titus, who is also appearing in ads on his behalf.

Reid, who retired at the end of 2016 after more than three decades in Congress, is a polarizing figure in Nevada but popular with the state's left.

He built a well-organized political machine in the state and many of his hand-picked candidates have gone on to win their races. His family said earlier this month that he's now undergoing treatment for pancreatic cancer.

"Chris wishes Senator Reid and his family all the best in his recovery and appreciates everything he's done for Nevada," Giunchigliani's campaign manager Eric Hyers said in a statement. "Senator Reid said last October that he had endorsed Steve long ago, before Chris had become a candidate, so this is no surprise."

Hyers noted Giunchigliani has been endorsed by groups like the Nevada State Education Association teachers union and the Sierra Club.

She released her own ad Friday criticizing Sisolak for having staked out more moderate or right-leaning positions in the past, including having received an "A-" rating by the National Rifle Association in 2012.

"You deserve a Democrat for governor who actually is one," Giunchigliani said in the advertisement.

The ads were first aired before a two-week early voting period starts Saturday. Many Nevadans are expected to vote at the polls early to avoid long lines at voting centers on the June 12 election day.

Besides Sisolak and Giunchigliani, there are four other lesser-known Democrats running in the primary race.

The winner of the Democratic primary is expected to face Republican state Attorney General Adam Laxalt in November. Laxalt faces state Treasurer Dan Schwartz and six other Republicans in the primary.

Nevada has not had a Democratic governor since Bob Miller left office in 1999. Democrats, anticipating for a "blue wave" around the country this year driven by backlash to the president, are hoping to flip the governor's seat in the swing state.

Popular, moderate Republican Gov. Brian Sandoval is on his way out because he's term-limited.