Generally popular but politically ambiguous, Ahn Cheol-soo was to return to South Korea on Monday after months of self-imposed exile from politics in the United States.

If the circumstances were bad for the former professor when he left the country on Dec. 19, the day of the presidential election won by his former conservative rival Park Geun-hye, they are hardly more favorable now for the novice politician.

Ahn will be running in the April 24 by-election in the constituency of Nowon-C of Seoul, a seat usually held by a liberal candidate, according to his aide.

Threatened by Ahn’s decision, the minor Progressive Justice Party, whose star member Roh Hoe-chan was stripped of his seat in the constituency upon a court conviction, has slammed the move and decided to nominate Roh’s wife and civic activist Kim Ji-sun to go up against Ahn.

With the main opposition Democratic United Party also planning to nominate its own candidate for the seat, the race in the usually non-competitive constituency could turn into a bloodbath of opposition contenders.

Ahn caused an unprecedented trend in politics last year by making his political debut as a presidential candidate with zero experience but commanding strong support ratings throughout the race on the platform of new politics.

But his drawn-out hesitation about his bid and an alliance with the DUP, not to mention little to no political base and middle-of-the-road political and policy standing resulted in his failure in the race of conservatives versus progressives.

Now, he returns to confusion and public angst against the government and the rival parties locking horns at a time of crisis, but also, at the most opportune moment for him to prove he was more than hype.

Ahn’s difficult task is to prove himself to be strong enough to smart his way through the bipartisan dynamics, but also maintain the “common sense” that he is so widely loved for.

It will be about how Ahn ― hopefully clearer and sterner this time ― creates another wave in the political battlefield where, in the face of allegiances, common sense seldom wins.

By Lee Joo-hee (jhl@heraldcorp.com)