The approval ratings for potential presidential candidate Ahn Cheol-soo rose after he appeared closer to running in the election and laid out his political vision through a new book and TV appearance.

According to a survey conducted by local pollster RealMeter on Tuesday, the Seoul National University professor overtook ruling Saenuri Party frontrunner Park Geun-hye with 48.3 percent to 45.2 percent in a hypothetical one-on-one match-up. Ahn’s support edged up 0.7 percentage point from the previous day and Park’s dropped 2.3 points.

The shift came after his book publication last Thursday and his appearance on a popular television talk show on Monday night.

In a multiple contest, Ahn reached 28.2 percent, narrowing the gap with Park’s 32 percent. Ahn’s approval rose 4.5 percentage points from just before the program was aired, and 10.1 percentage points from last Wednesday before his book was released.

His rise resulted in a fall in support for leading liberal candidate Rep. Moon Jae-in, former presidential aide and senior advisor of the main opposition Democratic United Party.

“The undecided center-left voters flocked over to Ahn as soon as he broke his long silence and came into the public light,” said Lee Taek-soo, head of the pollster.

“His numbers, however, have always fluctuated frequently and are expected to see further changes, depending on his actions.”

The political rookie, despite growing expectations, has not yet announced his bid for the year-end presidential race. However, he hinted at doing so, should his book and television appearance bring in sufficient public support.

“Approval ratings should be the easiest way to measure the people’s support for Ahn,” said Jae Jeong-im, professor of Semyung University who helped Ahn compile his book.

“He pledged to hold press conferences and keep a close watch on media feedback and social networks as well.”

By Bae Hyun-jung (tellme@heraldcorp.com)