By winning a parliamentary by-election in a Seoul constituency Wednesday, former independent presidential runner Ahn Cheol-soo joined the political establishment he has criticized for turning a deaf ear to the public. Shortly after his election, Ahn said his win reflected voters’ aspiration for new politics.

His successful political comeback, which came just months after his withdrawal from last December’s presidential race, appeared to have been propelled by the public disappointment with President Park Geun-hye’s leadership style and the inertia of the main opposition Democratic United Party. The software mogul-turned-politician in his early 50s is set to retake the center stage in domestic politics, with all eyes on his future course.

Some critics say it has yet to be seen whether Ahn can set himself up as a successful politician by moving beyond preaching against established politics. Probably setting his sights on the next presidential election in 2017, Ahn is expected to take steps to lay the groundwork for achieving his eventual political goal. His moves will inevitably prompt changes in the political configuration, with attention focused on the relationship between him and the DUP.

The liberal opposition party, which failed to win any of the three parliamentary seats up for grabs in Wednesday’s by-elections, has hoped to form an alliance with Ahn. But he has turned a cold shoulder to the DUP, which gained his concession to field a unified contender against Park of the conservative ruling Saenuri Party in the last presidential poll.

Ahn is expected to move toward launching his own party in preparation for another round of by-elections in October or local polls scheduled for June 2014. It is said that he plans to go on provincial tours to broaden his support base, set up a policy institute and form a study group encompassing lawmakers from both the ruling and opposition parties.

The outcome of the October by-elections is seen to be a watershed for the realignment of the liberal opposition bloc, which would set the tone for the political landscape in the lead-up to next parliamentary and presidential polls. A strong performance by Ahn’s group would open the floodgate for DUP lawmakers’ exodus into its fold. A poor showing may weaken the impetus of his political ascension.

The main opposition party is likely to accelerate its reform work to get closer to mainstream voters with practical and moderate views. Though it added two parliamentary seats, the ruling Saenuri Party also appears to be in no position to remain complacent.

Ahn’s political comeback can be meaningful at least if it leads to the rival parties becoming more sincere toward political reforms, including reducing privileges for lawmakers, and paying heed to sensible voices from voters.