The Pheu Thai party expects to be voted back into office at the next election under the new constitution, said key party member and former deputy prime minister Chalerm Yubamrung.
Speaking to a group of former Pheu Thai MPs, Mr Chalerm said the party was likely to return to power after new elections, now expected in early 2016. He said voters in the North and the Northeast, which constitute the country's majority of voters, still back the party, and former prime minister Thaksin Shinawatra remains popular among those voters.
"The two conditions that could cause the Pheu Thai party to be defeated in the next election are that Thaksin quits politics or Thaksin dies," Mr Chalerm said.
He was confident former prime minister Yingluck Shinawatra would become the party's nominee for the top job again, so long as she was not rendered ineligible because of cases against her.
The National Anti-Corruption Commission has recommended the National Legislative Assembly impeach Ms Yingluck for alleged negligence in failing to stop corruption in the Pheu Thai government's rice-pledging scheme.
On Friday, the NLA indefinitely delayed the question of whether impeachments brought under the abolished constitution should proceed. Many NLA members believe the impeachments, if pushed, would widen division in society.
As a result, the party can't do anything but wait and see, Mr Chalerm said.
He conceded that another development that could derail the party's return is if the interim government can somehow lower the cost of living. If Prime Minister Gen Prayut Chan-o-cha solves such problems, people might want him to stay.
But Mr Chalerm said he does not believe speculation that the military will create a political party to pave the way for Gen Prayut to be elected PM. "Gen Prayut is smart," he said. "He won't do that."