Republican presidential candidate Marco Rubio speaks at a rally in Miami on March 14, 2016, on the eve of crucial primary voting. (RHONA WISE/AFP/Getty Images)

WEST MIAMI, Fla. – The sound quality was less than ideal and the crowd size was modest, befitting a campaign that has sputtered in recent weeks and stands on brink of elimination.

But Sen. Marco Rubio, holding his final rally of the Florida primary campaign in the city where he started his career in elected office 18 years ago, delivered an optimistic speech in English and Spanish that served as a tribute to his hometown supporters.

“No matter where I go or what I’ll be, I'll always be a son of this community,” Rubio told the hundreds who gathered to hear him speak outdoors at a recreation center Monday night.

Rubio spoke in the back of a pickup truck where he was joined by his four children. At first, the audio was muffled because the bullhorn he spoke into didn’t carry the sound so well to the rear of the event.

“We got a better bullhorn,” he said after a few minutes, switching it out.

Rubio, who embarked on a career in politics as a West Miami city commissioner in 1998, told the crowd he envisioned being nominated at the Republican convention this summer and eventually being sworn in at the White House next year.

But to do so, he will have to overcome a series of immense obstacles, beginning with pulling off a huge upset in his home state on Tuesday, where every recent public poll shows Donald Trump leading. Even Rubio’s supporters acknowledge that if he loses Florida, he has no feasible path forward in the Republican contest.

Rubio made a final push all day Monday, making his way down I-95 in a campaign bus from Jacksonville to West Miami.

“How many of you have already voted?” Rubio asked the crowd here. After some cheers he said: “Well, then you have free time tomorrow to find other people to vote!”