Senate Democrats who hoped to curb the filibuster in order to pass two partisan election overhaul bills were thwarted by two centrists in their own party in an expected outcome that highlighted persistent intraparty divisions.

Democrats Joe Manchin of West Virginia and Kyrsten Sinema of Arizona upheld their pledges to preserve the filibuster, voting against a change in the rules supported by all other Senate Democrats that would have required those who wanted to block the election legislation to engage in a nonstop floor speech.