It has been a grueling presidential campaign for incumbent and insurgent alike. President Hugo Chavez appears spiritless and detached as he goes through the motions, in part reflecting his ongoing serious medical condition.

Challenger Henrique Capriles admitted during an appearance Tuesday on comedian Luis Chataing's popular nightly television program that he too was tired, but added that the unprecedented crowds that turn out wherever he goes keep him energized. Capriles' dual competitive advantage: At age 40, he is 18 years younger than his opponent and apparently in excellent health.

Following Capriles' event five days earlier, which attracted more than a million enthusiastic supporters, the Chavez campaign mounted a mass rally of its own in Caracas on Thursday. Government workers were ordered to attend the climax of the president's campaign, and 2,200 buses brought some 90,000 additional Chavez supporters to Caracas -- the latter a huge government expense, at nearly $3,500 per bus per day, plus more than $100 per passenger per day.

Heavy rains cut the event short. Observers attending or watching on television agreed that Chavez showed nothing of his once-remarkable enthusiasm and energy. The spellbinding charisma, key to the longtime leader's renown, was missing, and that reflected in the dampened enthusiasm of the 300,000 attendees.

Chavez's remarks consisted of a listless recitation of "Vivas!" for every socio-political constituency he could muster, repeated several times. One observer termed it "an old, weakened warrior's farewell."

Also on Thursday, Capriles spent his last campaign day visiting three communities far from Caracas: San Carlos, San Fernando and Barquisimeto, the country's third-largest city, where 250,000 supporters voluntarily greeted him.

As Sunday's election approached, it appeared voters had largely made up their minds. Respected pollster Consultores 21 found that undecided voters shrank from 7.7 percent to just 1 percent during September.

The firm's latest poll of 1,546 registered voters, taken between Sept. 27 and Oct. 2, indicated a 77 percent voter turnout and gave Capriles an advantage of 52 percent to 47 percent. The firm noted the study's 2.5-point margin of error could result in either a Capriles blowout or a razor-thin Chavez victory.

As expected, Chavez's campaign challenged the results, citing several polls showing Chavez with a large lead.

The enormous and spontaneous citizen turnout at every Capriles stop, which far outstrips Chavez's conscripted crowds, reinforces the pollster's findings. Independent observers Robert Bottome and Enrique Ter Horst predict victory for Capriles. Sources close to his campaign say internal polls suggest a 5-to-8-point margin for the challenger, which would translate to a winning margin of between 725,000 and 1,160,000 votes.

While it appears the Chavez era may well be ending, no one is quite sure how Chavez would accept defeat. In the event that Capriles wins by a landslide, as predicted by Ter Horst, many expect the president to hand over power gracefully. Ter Horst believes a victory of 5 points or more would convince Chavez and his supporters to step aside.

However, Consultores 21's latest soundings suggest a mere 4.6-point margin -- or 676,000 votes out of 14.7 million cast. This could conceivably convince Chavez' hard-core supporters to do whatever is necessary to maintain power.

In such a situation, a peaceful power transfer would have to rely on troops led by Gen. Wilmer Barrientos, chief of Venezuela's Strategic Operational Command, to keep the chavistas under control. As a longtime Chavez loyalist, the general's even-handedness is far from certain.

At the conclusion of last Sunday's massive spontaneous display of support, Capriles stood on the podium and reiterated once more the underlying theme of his campaign: "Nobody should be afraid; all we must fear is to do nothing!"

Then, as the throng cheered their support, his mother at his side, the devoutly religious Capriles pointed at the sky and said, "Somewhere up there in heaven, my grandmother will be celebrating!"

In just eight months, Capriles' campaign has gone from strength to strength, to a point where his reach for the sky may in fact succeed in Sunday's election.

Geopolitical analyst and former diplomat John R. Thomson focuses on the developing world. Former Venezuelan career Ambassador Norman Pino De Lion is a frequent contributor to leading Venezuelan newspaper El Universal.