D L Ravindra Reddy of Congress appears to be also in the fray only for the sake of it.
The lone question political pundits are asking is not who will win Kadapa but what will be Jagan`s margin of victory.
Jagan got elected to Lok Sabha from Kadapa in 2009 on Congress ticket by a margin of over 1.75 lakh votes.
But, he quit the party as well as his parliamentary membership in November last year to float his own political outfit.
He is fighting the May 8 bye-election on behalf of his fledgling party, staking claim to his late father Y S Rajasekhara Reddy`s "political legacy."
Now, Jagan`s aim is to secure a victory margin of over two lakh to three lakh votes so as to send a resounding message to the Congress about his political might.
Interestingly, the Congress too is playing the "legacy" card against Jagan claiming Rajasekhara Reddy remained a "true Congressman" till his last breath unlike Jagan who quit the party only to fulfil his "political over-ambition" of becoming the chief minister.
Jagan, on the other hand, is banking heavily on the sympathy factor and has been going to the extent of terming the Kadapa by-poll as a fight between Sonia Gandhi and YSR.
"It is a fight for self-respect," he tells voters as he seeks a mandate for him so as to teach a lesson to the Congress high command.
The Congress has raised the BJP bogey against Jagan to attract the two lakh-odd Muslim voters in the Kadapa after the latter indicated that he would consider aligning with the saffron party if it promised ten per cent reservation for Muslims across the country.
Jagan himself has promised to provide reservation for Muslims in politics as well.
The Telugu Desam, on the other hand, has focused entirely on the issue of corruption, showcasing how Jagan has allegedly amassed huge ill-gotten wealth between 2004 and 2009 when his late father was the Chief Minister.
Jagan, however, is unperturbed over the tirade against him by the Congress and the TDP as he is confident of riding the sympathy wave.
Of the seven Assembly segments in Kadapa Lok Sabha constituency, Jagan has a clear edge in four while the TDP is strong in two.
The TDP is giving Jagan a run for his money in Jammalamadugu and Kamalapuram segments while in Mydukuru too it is gaining enough strength.
Incidentally, Congress candidate and state Health Minister Ravindra Reddy belongs to Mydukuru, but in the bye-election the tide is apparently turning against him.
Kamalapuram is the native place of TDP`s Mysura Reddy, currently a member of Rajya Sabha, and hence he is able to muster strong support.
However, Congress MLA from Jammalamadugu, C Adinarayana Reddy, is a staunch Jagan-loyalist and has been actively campaigning for the former MP.
But, the Congress appears to stand no chance in this segment, as former TDP minister Ramasubba Reddy has done enough ground work to keep his party flag flying high.
By ensuring a good margin for Mysura Reddy in the by-poll, Ramasubba Reddy would like to re-establish his hold on the constituency.
In Badwel, Congress MLA Kamalamma too sailed with Jagan initially but returned to her parent party as soon as the by-election campaign kicked off.
However, this has not helped the ruling party any way as former MLA Govinda Reddy, who is on Jagan`s side, has proved mightier than her, thereby ensuring solid backing for the YSR Congress.
The TDP has sitting MLA M Linga Reddy in Proddutur but he may find it difficult to check the Jagan juggernaut.
Same is the case in Kadapa town where Congress minister Md Ahmedullah is finding it touch to match Jagan.
Pulivendula Assembly segment could be the lone face-saver for the Congress, thanks to YSR`s younger brother Vivekananda Reddy.
Incidentally, Vivekananda Reddy is himself locked in a battle with his sister-in-law Vijayalakshmi for the Pulivendula Assembly seat, by-election for which is being simultaneously.
"One vote (Assembly) for me, one vote (Lok Sabha) for my nephew (Jagan)," has been Viveka`s slogan for most part of the by-poll campaign despite the uncle-nephew duo being at loggerheads over the YSR family`s political course.
Starting from Chief Minister N Kiran Kumar Reddy, his predecessor K Rosaiah, Praja Rajyam Party president K Chiranjeevi and a few Union ministers campaigned for the Congress while more than half of the state cabinet ministers are busy on poll duty in Kadapa for about a month now.
The outcome of the by-election may only result in heartburn for all of them.