First minister Mark Drakeford said he is still urging AMs to not support the UK's Withdrawal Agreement Bill despite accepting that Brexit will happen at the end of January.
Assembly Members will be asked whether they consent to the bill because of its impact on devolution.
The First Minister said he is particularly concerned about the UK government's planned Shared Prosperity Fund, which will replace European Aid to Wales.
The EU lets the Welsh Government distribute the money but Westminster could demand a bigger say in what is spent where.
As is usual at the First Minister's news conferences, there was a large European Union flag next to him, as well as Welsh and British flags. He was asked if the EU flag would disappear after Brexit.
Like occasionally flying the EU flag, asking AMs to vote against Brexit legislation is largely symbolic.
The UK Government can and will press on without the approval of the National Assembly. Mark Drakeford stressed that his government's priority for 2020 is to concentrate on the areas where it has the power to act, such as health, education, housing and the environment.
It is on those issues that the First Minister can expect to be judged in the 2021 Assembly elections, although it seems likely that arguments about Wales -and Britain's future relationship with the EU will also rumble on into next year.