Kyrsten Sinema has indicated – or simply confirmed – that Democrats’ push to change Senate rules to allow for the passage of voting rights legislation is indeed doomed.

In a speech on the Senate floor delivered shortly before Joe Biden was scheduled to arrive on Capitol Hill to attempt to force the issue, the Arizona senator said: “While I continue to support these bills, I will not support separate actions that worsen the underlying disease of division infecting our country.”

Those separate actions would involve abolishing or modifying the filibuster, the rule which empowers the minority by setting a 60-vote threshold for most legislation.

The Senate is split 50-50 and controlled by Democrats via the vice-president, Kamala Harris. Democratic senators represent vastly more voters than Republican senators, a point often made by supporters of filibuster reform.

Democrats who favour change also point out that federal legislation is needed to counter Republican attempts to restrict voting among minorities which tend to favour Democrats, by means of restrictive laws at the state level.

Voter suppression laws are also at issue, as Republicans who support Donald Trump’s big lie about electoral fraud seek to instal allies in key posts and to make it easier to overturn election results.

Nonetheless, Sinema and her fellow moderate Joe Manchin, of West Virginia, have remained steadfastly against filibuster reform – even though both support some form of federal voting rights protection.

They fear the ramifications of filibuster reform if and when Republicans take back the chamber, which could well happen later this year. Some observers suggest that is naive, as Republicans under Mitch McConnell, a man who has made constitutional hardball an art form, may well dynamite the filibuster themselves.

Either way, without Sinema and Manchin, all efforts on the issue by Biden and the majority leader, Chuck Schumer of New York, are doomed to fail.