"When the time comes, we will sit together and divide the seats. We will fight together and Narendra Modi will be again the prime minister in 2019," he said at the India Today Conclave East here last night.
He was replying to a question on whether the BJP might not feel the need for JD(U)'s support in the elections in 2019.
"Alliance is a give and take. When both the partners feel they will benefit from it then only it will work. We will fight together with Nitish Kumar-led JD (U) in the 2019 Lok Sabha polls," he said.
His remarks assume significance as there were some discordant voices from leaders of both the parties on seat sharing for the next general elections earlier.
After a meeting with MPs from Bihar, BJP chief Amit Shah had asked partymen to strengthen it down to the booth level in all 40 Lok Sabha seats in the state. The JD(U) also appealed to its workers to brace for contest on all the 40 seats.
RJD supremo Lalu Prasad and other opposition parties leaders had used the occasion to attack Nitish Kumar, claiming that he was marginalised by the saffron party to avenge an incident in 2010 when he had cancelled a dinner for BJP leaders over a tiff with Narendra Modi, the then chief minister of Gujarat.
"The JD(U) and the BJP are made for each other," Sushil Modi said.
"Nitish Kumar has been our partner for 17 years and again the JD(U) and the BJP have come together, it is a natural alliance," said the senior BJP leader, who also served as the deputy chief minister in the earlier NDA government.
The JD(U) had severe ties with the BJP in June 2013 over elevation of Narendra Modi as the prime ministerial candidate.
After collapse of an alliance comprising the JD(U), the RJD and the Congress in July this year, Nitish Kumar and the BJP once again joined hands after four years to form a coalition in the politically sensitive state.
Sushil Modi's allegations against Lalu Prasad and his family of acquiring benami properties had played an important role in the disintegration of the alliance comprising the JD (U), the Congress and the RJD.
When the JD(U) and the BJP coalition was sworn in again on July 27 this year, Sushil Modi was made the deputy chief minister.
The senior BJP leader dismissed speculation that a seat- sharing adjustment, in which the JD(U) would also be accommodated, might upset the sitting BJP MPs if they were denied tickets.
"What is the guarantee that every MP will get party ticket a second time? And what will they do by getting upset. If people make up their mind then it hardly matters who is getting ticket or not," Sushil Modi said.
Sushil Modi accused Lalu Prasad of being "chaotic, disorganised and an irresponsible man".
"No gentleman can work with a person like Lalu Prasad. An unnatural alliance (of the JD(U), RJD and Congress) died a natural death. The day Nitish Kumar left the NDA, I knew this alliance (with the RJD) would not work but, I never thought it would break so soon," he claimed.