The backdrop: News that Corker may choose to run for reelection began after several GOP leaders voiced concerns about losing the seat to a Democrat, prompting Corker's spokeswoman to tell Politico that he's "listening" to those concerns.

• If he does choose to run, he'll be up against Republican Rep. Marsha Blackburn in the primary, with former Gov. Phil Bredesen likely to represent the Democrats in the general.

What they're saying:

• "Marsha is much more of a fighter than Corker, and she’s not as tentative about shaking the status quo — [our supporters] appreciate that," Jenny Beth Martin added.
• "No grassroots folks would be enthusiastic about it … Just upon hearing that Corker was thinking about retirement, our folks gave $25k more to Marsha’s campaign," Ken Cuccinelli, former Attorney General of Virginia and President of the Senate Conservatives Fund, told Axios. "As for Trump, talk about burning a bridge! The president's base isn’t going to forget that ... and it not like he’s been so good on other things."
• "The conservative movement across all aspects are aligned and united behind Blackburn," a source close to the conservative movement told Axios.
• Other sources pointed to polls — conducted largely by conservative organizations including Club for Growth, WPA Intelligence, and the Senate Conservatives Fund — that show Rep. Blackburn ahead of Corker in a hypothetical match-up.

The other side:

• “Sen. Corker and President Trump have a good relationship and talk periodically about a number of issues," a source familiar told Axios. "The senator continues to attend meetings at the White House, as he has throughout the president’s time in office.”
• The source also pointed to an internal poll, conducted in late January by Glen Bolger of Public Opinion Strategies and obtained by Politico, that shows Bredesen narrowly edging out Blackburn 47 to 45.