Assuming for a moment that the Senate fails to pass a healthcare bill before the Sepetember 2017 deadline, can they still use budget reconciliation to pass a massive bill that includes both tax reform and Obamacare repeal in the same bill during the next fiscal year? Is there any reason why a budget reconciliation bill needs to only address one issue like taxes or healthcare?
There is nothing in the rules preventing a Reconciliation bill from addressing two or more areas. Traditionally they've been used to pass giant omnibus bills funding the entire government after Congress failed to pass some or all of the appropriation bills.
The greater problem here is that the Republicans are having trouble uniting around a healthcare bill. If there's only forty-nine votes at most for any version, then they won't be able to pass it next year either.
Worse, what if they hit the same problem with tax reform? Say Rand Paul and Mike Lee are against the tax reform proposal. So they drop out. Susan Collins and Lisa Murkowski are against healthcare reform. So now we have four opponents to the combined bill where each issue alone only had two.
The only way that this works is if the healthcare opponents like tax reform so much that they vote for healthcare reform to get it. But that doesn't seem to be the case. Collins and Murkowski haven't been trumpeting the need for tax reform. Perhaps that will change once there's an actual proposal to like or dislike, but I wouldn't bet on it.
And all this is dependent on the tax reform bill. There currently isn't one to pass. They'd have to write it first.
In theory there is nothing preventing this. In practice, merging the two is likely to make them more difficult to pass.
Is there any reason why a budget reconciliation bill needs to only address one issue like taxes or healthcare?
Bills routinely contain completely unrelated amendments. And not just in the US, either - this happens in all democracies. There's even an actual term for such a thing.
Can they still use budget reconciliation to pass a massive bill that includes both tax reform and Obamacare repeal in the same bill during the next fiscal year?
They could... if such a thing passes - big if.