ARI SHAPIRO, HOST:
The number of Republicans planning to leave Congress this year has now reached a record level. Today, California Congressman Darrell Issa said he plans to retire at the end of 2018. In total, there are now 31 Republicans planning to retire from the House - the most ever in a single year. That's not a good sign for the party heading into this year's congressional elections. NPR political reporter Jessica Taylor has been studying the 2018 midterm map. Hi there.
JESSICA TAYLOR, BYLINE: Hey, Ari.
SHAPIRO: Let's start with Darrell Issa. He just made this announcement today. He's been in Congress 17 years. He was a high-profile opponent of the Obama administration. How much of a surprise is this?
TAYLOR: I don't think it's really shocking when you look at his district that really has changed over the past few years. Issa is one of four Republicans retiring from a district that Hillary Clinton won. He only won re-election last time by about 1,600 votes. So when he's looking at his re-election chances in a very tough cycle, I think he had a decision to make.
SHAPIRO: So that's his district in California. But nationally, these 31 Republicans not seeking re-election covered the entire map. What's going on?
TAYLOR: I think that some of them are driven by re-election concerns like Issa. But then you also have the vast majority of Republicans that are leaving - maybe they've just been there for a while, too. It's time to leave. They maybe want another career. And many of these are still safe Republican seats that the GOP will still hold. Some of them are committee chairmen that are termed out. They're not going to be able to lead the committee again. And going back to being a backbencher isn't necessarily as appealing. And many of them that are retiring are actually running for other seats. They're running for Senate or governor, so that means that they're looking at this and saying, OK, maybe this isn't such a bad environment completely.
SHAPIRO: We often hear that the congressional map favors Republicans, and that even if more people vote for Democratic members of the House of Representatives, Republicans can still control the chamber. How optimistic are Democrats that they could actually take back the House in 2018?
TAYLOR: I would say they're cautiously optimistic. Some of these retirements from Republicans are encouraging for them, but they also have their own retirements to be concerned about, too. There are 15 Democrats retiring, and some of those sit in districts that Trump won. They are looking at a universe of maybe as many as 90 competitive seats. And as you mentioned, with the way that the map is drawn, Republicans have an advantage going in inherently. But when they look at the trends that are working their way and the fact that the president's party typically loses around 28 seats in their first midterm, it's all encouraging for Democrats.
SHAPIRO: And Democrats need to pick up how many seats to win control?
TAYLOR: They need to pick up 24. It's out there. But as you mentioned, there are still a lot of things that are still working in Republicans' favor because of the way that this map is gerrymandered. So both Republicans and Democrats acknowledge that the House is absolutely in control. I think it's still very early. But when you see this trend of retirements, it's not encouraging for Republicans. I talked to former Congressman Tom Davis of Virginia who was a chairman of the National Republican Congressional Committee. And he said, you know, he's not seeing it as a tsunami yet, but he mentioned if you see other members in these marginal districts that Clinton won retire, that's when it becomes really worrisome for Republicans.
SHAPIRO: NPR's Jessica Taylor walking through the congressional map with us. Thanks very much.
TAYLOR: Thank you.