Worrying about their livelihood and longing for political reform, people in their 40s, especially those who are middle class and reside in the Seoul metropolitan area, are emerging as a decisive section of the electorate for the close presidential race.

Their potential to determine the December election was pronounced in last week’s opinion polls.

Polls show that the age segment has sharply shifted toward Ahn Cheol-soo, a liberal-minded independent, following his much-awaited announcement of his presidential bid last week. 

The former software tycoon, doctor and professor has run neck-and-neck in polls for months against Park Geun-hye, the presidential nominee of the ruling Saenuri Party.

Forty-somethings are believed to hold the casting vote as they oscillate between younger voters with a progressive disposition and those in their 50s or older, who are deemed largely conservative.

The 20- and 30-somethings tend to lean toward either Ahn Cheol-soo, who has polled as one of the figures young Koreans most look up to, or Moon Jae-in, who is running under the banner of the main opposition Democratic United Party.

In contrast, Park boasts rock-solid support from elders and conservative voters. 

In a survey by SBS and TNS Korea, Ahn led Park 48.2 percent to 42 percent in a hypothetical two-way showdown. It was conducted on 968 adults from Wednesday to Thursday, with a confidence level of 95 percent and a margin of sampling error of plus or minus 3.1 percentage points.

A separate poll by Gallup last week also showed Ahn topping Park by 5 percentage points with a 49 percent support rate. Though the lead is within the margin of error, it marks a stark contrast to the firm’s other survey a week ago in which the former Saenuri chairwoman held a 9 point edge, benefitting from newly emerged controversy over real estate and financial investment surrounding Ahn.

Ahn’s lead was also detected in a poll by Realmeter with a 49.9 percent supporting rate, versus Park’s 44 percent.

The prime mover in the latest uptick in his approval rating are people living in the Seoul metropolitan area, 40-somethings and middle class voters.

The Gallup record showed that among suburban Seoul residents the figures for the AhnLab founder shot up to 53 percent from 42 percent on a weekly basis, while Park’s slightly edged down by 1 percentage point to 40 percent.

The most striking shift appeared among those in their 40s. Fifty-nine percent of the respondents selected Ahn last week, representing a whopping 22 percent rise from a week earlier. Park’s rates plummeted from 46 percent to 35 percent.

More middle class electors also voted for Ahn. His numbers jumped to 55 percent from 44 percent during the same period. Park lost 2 percentage points to 40 percent.

By Shin Hyon-hee (heeshin@heraldcorp.com)