When Miami-Dade Mayor Carlos Gimenez proposed cutting a deal earlier this year to benefit the struggling company that wraps baggage at Miami International Airport, county commission Chairman Joe Martinez cued up a video of a meeting from two years earlier.

It showed then-Commissioner Gimenez, warning the firm that it would not be cut any slack if it failed to deliver on its lofty revenue projections. Yet here he was, appearing to do just that.

Gimenez, now the mayor, watched the video poker-faced from his seat in the chambers.

It was one of the first public salvos fired in the mayoral campaign, which has played out for months in ways both obvious and subtle on the commission dais.

Featuring Gimenez on the video was a mistake, Martinez says now. But as the fundraising underdog challenging the incumbent mayor, Martinez has not been shy about using his bully pulpit to capture the attention of television cameras.

The mayor favors a more low-key style. He’s given plenty of interviews, most delivering a similar message about promises kept: He lowered the property-tax rate, trimmed the budget and merged county departments.

Gimenez has decried dais politics, like when Martinez and other commissioners who earlier had signed off on a lower tax rate loudly balked at imposing additional union concessions they knew would be necessary.

“The campaign from the dais started the day I became mayor,” Gimenez said.

Martinez has said he would run for mayor since 2010, when he was appointed chairman. After the recall of Mayor Carlos Alvarez last year, Martinez, first elected in 2000, flirted with running for the open seat, but decided to finish his term instead — giving him a powerful launching pad for his current mayoral bid.

Five lesser-known candidates have also qualified for the mayor’s race: Edna Diaz, Gary Johnson, Farid Khavari, Helen Williams and Denny Wood.

Political observer and former Hialeah Mayor Raul Martinez, who supported Gimenez last year, said Martinez has “absolutely” used the chairman position to his advantage.

“He salivated when we had that vacuum of not having a mayor,” said Martinez, no relation to the commission chairman. “He thought he was the king of the road at the time.”

Now, however, Martinez says the commission chair is creating issues and making statements “he can’t back up.”

Case in point: When news broke that hundreds of county vehicles had been stockpiled in a county-owned parking garage for five years, records showed that Gimenez, Joe Martinez and other commissioners had been informed about the issue two years earlier.

Still, the Gimenez administration bungled the controversy by taking days to explain that the vehicles were there because of a decision by the prior administration. Meantime, Martinez wasn’t shy about criticizing both adminstrations. Then he vowed to create a committee to look into mismanagement. Two months later, the issue is all but forgotten, though at the time Martinez looked like he was setting the agenda.

Raul Martinez scoffed at the chairman’s reaction.

“Those cars were not bought recently,” he said.

“He was on the commission. Where was he? Why didn’t you ask the questions before?” he said, as if addressing the chairman.

Chairman Martinez, however, says the commissioners’ role is limited to setting broad policies and not to managing county agencies.