Story highlights Republicans are trying to find a way to pass changes to tax law without Democratic help

The tax rates President Donald Trump wants appear unable to qualify under Senate rules

(CNN) President Donald Trump's ambitious goal of reducing the corporate tax rate from 35% to 15% without concern over deficits has a fatal problem: Senate rules.

That's per the Joint Committee on Taxation, which in a private analysis requested by House Speaker Paul Ryan and obtained by CNN, found that a significant corporate rate cut (in this case, from the current level of 35% to 20%, which House Republicans have proposed) for just three years would result in deficit increase after 10 years.

Why does that matter?

Well, in order for Republicans to move any tax cut at that level through Congress, they would have two options: find Democratic votes, or try to go through reconciliation, a budget process that would allow Senate Republicans to pass a bill with just 51 votes -- or in other words, no Democratic support (Republicans control 52 seats in the chamber). The only caveat: The tax bill would not qualify for a simple majority vote if it adds to deficits beyond 10 years.

Democrats have made clear that they would be unlikely to support a substantial rate cut without anything sizable in return. That leaves reconciliation as the only pathway.

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