New Senate map shows Republicans are increasingly vulnerable

WASHINGTON — Amid the constant political chaos of 2020, there have been a few consistencies. One of them has been a growing Democratic advantage in this fall’s congressional races, particularly the Senate.

For Democrats, the potential for pickups is growing and affecting some places where a tight general election race is not a normal occurrence. From the Mountain West to the South, the list of competitive Senate races for the GOP looks different this year.

Going into this election cycle Republicans knew they were going to be defending a challenging...