The Senate has passed a provision that would allow the State Department to deny passports to citizens with "seriously" delinquent taxes. They define seriously as more than $50,000 but that amount would adjust for inflation in future years. There would also be exceptions when the tax payer has a payment plan with the IRS or a hearing is pending.
The provision is part of the highway transportation bill. That bill is expected to go for a final vote later this week. The house is planning on taking up the bill next week. So this provision has several steps before it can become law.
This comes on the heals of the decision to allow deportation for unpaid taxes. It appears that the IRS will use all the levers at their disposal to ensure payment.