As already noted here, on June 22, the U.S. Supreme Court issued a ruling in City of Los Angeles v Patel that has implications for ballot access lawsuits. The case itself has nothing to do with election law, but clarifies when plaintiffs can make facial challenges instead of just as-applied challenges.
This commentary by Ian Millhiser at Think Progress develops this concept, although Millhiser explains it in relation to laws restricting abortion.
The facial versus as-applied challenge matter has been especially vexing when plaintiffs recently have filed lawsuits against early petition deadlines. Currently such lawsuits are pending in Arizona, Arkansas, and South Dakota. Thanks to How Appealing for the link.