Charles E. Grassley won with 66.0% of the vote (588,880 votes), ahead of John O. Roehrick with 33.6% (299,406 votes).
The margin between the first two candidates was 32.5 percentage points (289,474 votes). The party margin (Republican share minus Democratic share) was a Republican lead of 32.5 points.
Compared with the previous comparable race in the same area, the party margin moved 44.3 points toward Republicans. The winning party changed.
891,762 votes were counted in this race, for 3 candidates or options.
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