Conservative members would have the final say on any future plans to form a coalition Welsh Government with other parties if Paul Davies becomes Tory assembly group leader, he has pledged.
Launching his campaign, in Usk, Monmouthshire, he said it was time members shaped the party's future.
Deals with other parties are seen as the Tories best chance of entering government in Wales after 2021.
Plans for a Plaid-Conservative Lib Dem Welsh Government in 2007 fell through.
Dubbed a rainbow coalition, the proposals unravelled after a split at the top of the Liberal Democrats over them.
This summer's leadership contest was triggered by Andrew RT Davies's resignation in late June, after he felt he had lost the support of his colleagues.
Paul Davies's manifesto, Changing Wales, includes proposals to "introduce democratic accountability" to health boards, currently appointed by Welsh ministers and "pursue a low tax agenda".
Partial control of income tax is being devolved to Wales next April.
In a section of the document entitled "Empowering Members" he writes: "I am delighted members are having their say in this contest, but they need to be consulted even more.
"I will ensure that if a coalition deal is ever proposed with other parties, then members will be invited to a special post-election conference.
"Members should feel valued and have ownership of the Welsh Conservative Party and it is time they shaped its future."
Addressing supporters in a pub in the centre of Usk, Paul Davies promised to energise and unite Welsh Conservatives and give the the best chance of snatching key marginal seats from Labour at the next assembly election in 2021.
The AM for Preseli Pembrokeshire said: "I believe I have the skills and the experience to lead our party into battle in constituencies like Cardiff North, Gower and Wrexham with a slate of genuinely diverse candidates from across Wales.
"It's in these Labour-Conservative marginal constituencies that the next election will be decided."
Mr Davies's rival for the position, South Wales West AM Suzy Davies, is due to begin her campaign next week.
Postal ballots for the leadership contest will be sent out on 15 August with the winner declared on 6 September.
The 12-strong Conservative group is the second biggest in the assembly and has been in opposition to Labour-led administrations since devolution in 1999.