(CNN) House Democrats are carefully laying the groundwork to obtain President Donald Trump's personal tax returns in the new Congress, hoping to build public support for their effort as they prepare to confront a defiant President.

Incoming House Ways and Means Committee Chairmen Richard Neal, the only Democrat who has the power in Congress to obtain Trump's taxes, had hoped Trump would hand them over willingly, but a source familiar with ongoing discussions says public comments from the President's allies have made it clear that asking nicely would be a "waste of time" and that likely the most efficient way for Neal to ask for the returns is to do it formally. In that case, Neal would ask the Treasury Department for the returns in the new Congress. When that would actually take place is still under discussion.

"They have to have a reason for wanting them and I fail to see a reason. They can't just look at them. It has to be linked to some wrongdoing," Giuliani told CNN on Tuesday.

"We will fight it in court and I think we would win unless they had some specific allegation."

Read More