Old law: If you don’t have a presence in a state, then you are NOT required to collect sales taxes. In my state (Colorado) for example, if you sell less than $1000 worth of goods online or otherwise to buyers residing in the state, you are exempt from collecting sales tax. If you sell more than $1000 annually, you must apply for a sales tax collection license from the state, which in some cases, requires posting a cash bond.
New law, effective today: who knows...literally everything from this point forward is subject to change. For example, some states have a "de minimis" (too small to mess with) annual sales threshold of $100,000, where they do not enforce penalties on sellers who do not collect their taxes. But, there's nothing to stop states from lowering that threshold.