A nationwide sales tax for online / interstate transactions is necessary to ensure that our Governments continue to obtain crucial funding from Sales Tax, while ensuring a uniform, single-cost to the merchant and customers.
A nationwide sales tax would also help level the playing field for online and offline businesses.
The laws being drafted now by individual States are at risk of clashing with each other, making States challenge each other for cash. Furthermore, many would require the collection of "discretionary" taxes which would put an un-necessary burden on small business owners, leading to a contraction in the growing eCommerce industry.
A single, uniform tax is good for business, and good for consumers!