In the history of presidential elections in the United States has a major political party ever functionally conceded defeat months before the general election and ran its house/senate candidates as checks on the opposing party's candidates power once they assumed the presidency?

by NeoPhiloMath

Recently it has been in the news that officials and house/senate candidates for the Republican party are considering writing off their general elections candidate and instead running as "checks" on the power of a presumptive Democratic president. Has this happened before in previous US presidential elections or would this strategy be historically unprecedented in US politics?

SRKincaid

Republicans ran Congressional campaigns in 1996 (Clinton/Dole) explicitly as a check against the presumed Clinton victory. (Clinton was up 8 points in October polling.) The NRCC warned against giving Clinton a blank check and pushed for voters in vulnerable districts to split their ballot.