The Story:
Next year the people of New Mexico (a state that voted for Hillary Clinton for President) will elect a new US Senator to replace Tom Udall (D), who will finish up his second term and who is not running for a third. This means that the Republican Party has a chance to pick up a seat to defend or pad its existing narrow majority in the chamber.
Declared Candidates:
A former Trump administration Interior Department official, Gavin Clarkson, is the only individual yet to have declared that he is running for the Republican Party’s nomination for this seat. Others are expected in due course to jump into the race.
On the Democratic side, there are three declared candidates: Maggie Toulouse Oliver, Ben Ray Lujan, and Giovanni Alexander Haqani. Oliver, New Mexico’s Secretary of State, successfully pressed for campaign finance reform in the state. She boasts that she “took on the Koch brothers and won” on that issue.
The Thing to Know: 
Not only did New Mexico vote for Hillary Clinton in 2016, it voted for Barack Obama twice before that. It is seen as a ‘blue’ state. Its retiring Senator, Udall, stands out for (distinctively “progressive”) views on both gun control and conservation.