Trump might not be able to save Dean Heller

• The Republican tax law includes provisions that hit tax-exempt organizations, like churches, per Politico, which would require them to pay taxes for the first time ever. This matters because the GOP largely depends on religious voters, and 66% of Nevadans identify as Christians.

• Since late April, support of the GOP's tax law nationwide has slipped by six points, per a recent Monmouth University poll.

Why it matters: Democrats view Nevada's U.S. Senate seat as one of their best pickup chances in 2018, which would be a needed buffer given that the map is working against them.

The Trump factor: President Trump stumped with Heller in Las Vegas last weekend, where he acknowledged their initially "shaky" relationship, but he credited Heller for fighting for the GOP tax law.

• Senate Leadership Fund, the super PAC aligned with Mitch McConnell, plans to invest $11.2 million in the Nevada Senate race.

The bottom line: An endorsement from POTUS has proven to be helpful in some races, but Hillary Clinton won the state in 2016, adding to Heller's uphill battle.