Speaking to the Institute for Government earlier in the day, Morgan said the most recent opinion poll gave “two pro independence parties Plaid and the Greens a majority in Wales”.
“Separatism is now very much on the agenda in our nation,” she said.
She said the significance of that was “not reverberating as it should”.
“Support for independence tends to rise when politics feels stuck or uncertain, and it falls when people see devolution deliver.”
Devolution is the “best way to lower the temperature and raise trust”, she said.
“The UK government can play a leading role in helping us to resist separatism and the break up of the union. They can support us by giving us the tools to help improve life for the people in Wales.”
Following her speech, Morgan said the “threat to the United Kingdom will become real” if pro-independence parties came out top in Wales as well as in Scotland, where pro-independence SNP are hoping to return to government following May’s Holyrood election.
Plaid Cymru is vying for first place in the election. While it still supports independence, its leader Rhun ap Iorwerth has said he would not try to hold a referendum on the topic in a first term.
Following a recent opinion poll, Cardiff University estimated Plaid and the Greens combined could win a total of 56 seats – well over a majority needed to control the Welsh Parliament.
Plaid polled at 37%, Reform came second at 23%, the Greens at 13%, and Labour and the Tories in fourth place at 10% each, in the poll organised by YouGov for ITV, external.