With five weeks to go before Election Day, Democrats are still waiting for Donald Trump to create the nationwide swell that would be necessary to put the Republicans’ House majority into play. House races are often late to engage but, thus far, the developments have been a mixed bag for Democrats, keeping sizable gains out of reach.

The lack of vulnerable Democrats — and the resiliency of many Republican incumbents in the face of an unpopular presidential nominee — could amount to a historic election in the House, but not in the way one might think. The cycle could produce the fewest number of House seats to flip party control in 60 years.

[Roll Call’s 2016 Election Guide: House]

Just nine seats flipped party control in 1988, the fewest number since 1954, according to Vital Statistics on Congress (Table 2-5), a joint project of The Brookings Institution and the American Enterprise Institute. Eleven seats flipped in 1968 and 13 in 2004. Over the last 60 years, 30 House seats, on average, have flipped party control.

This cycle, just three seats are virtually guaranteed to switch parties — all because of redistricting — including Florida’s 2nd and 10th districts and Virginia’s 4th District. Democrats are struggling to lock away other takeover opportunities including Florida’s 13th District, which was drawn to be more Democratic and now includes all of former Gov. Charlie Crist’s home area, and can’t put away GOP Rep. John Katko, who represents New York’s 24th District, where President Barack Obama won handily in 2012.

The lack of widespread vulnerability at the House level is remarkable considering voters rewarded outside profiles and messages in the Democratic and Republican presidential primaries.

This week, we’re changing The Rothenberg & Gonzales Political Report/Roll Call rating in a dozen House races. But six changes are in favor of the Democrats and six in favor of the Republicans, which is just one piece of evidence that there isn’t the national wave that Democrats need to gain the 30 seats necessary to win back the House majority.

Six races shifted toward the Democrats:

• Arizona’s 1st District (Open; Ann Kirkpatrick, D) From Tossup to Tilts Democratic
• California’s 49th District (Darrell Issa, R) From Safe Republican to Republican Favored
• Florida’s 7th District (John L. Mica, R) From Republican Favored to Tilts Republican
• Michigan’s 1st District (Open; Dan Benishek, R) From Leans Republican to Tilts Republican
• New Jersey’s 5th District (Scott Garrett, R) From Leans Republican to Tilts Republican
• New York’s 19th District (Open; Chris Gibson, R) From Leans Republican to Tossup

Six races shift toward the Republicans:

• Arizona’s 2nd District (Martha McSally, R) From Republican Favored to Safe Republican
• Florida’s 13th District (David Jolly, R) From Democrat Favored to Leans Democratic
• Iowa’s 3rd District (David Young, R) From Tossup to Tilts Republican
• Michigan’s 7th District (Tim Walberg, R) From Tilts Republican to Leans Republican
• New York’s 24 District (John Katko, R) From Tossup to Tilts Republican
• Wisconsin’s 8th District (Open; Reid Ribble, R) From Tossup to Leans Republican

You can get the latest analysis and public polling in dozens of the most competitive House districts in the Sept. 30 issue of The Rothenberg & Gonzales Political Report.