It's your choice. You can either deduct it and lower your 2019 tax (or increase your refund) and then pay the tax on the 2020 conversion, or make it non-deductible on a 2019 8606 form and then use that basis to offset the 2020 tax next year. Which you do depends if you want a bigger 2019 refund and pay tax in 2020 or defer it to 2020.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
