Washington DC - Republicans in the Senate on Wednesday blocked a bill recognizing a legal right to contraception, introduced as part of a Democratic effort to highlight threats to reproductive freedoms as a key issue in November elections.

The legislation would have guaranteed the right to obtain and use condoms, intrauterine devices, and other birth control methods and for health providers to prescribe them and give advice free from government interference.

A recent poll by the Kaiser Family Foundation found that one in five US adults worries that access to contraception is "a threatened right likely to be overturned" following curbs on abortion implemented in some conservative states.

"In a perfect world, a bill saying you can access birth control without government interference should not be necessary," said Senate Majority Leader Chuck Schumer.

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"But given the erosion of reproductive rights in America today, it is absolutely vital."

The bill needed the support of 60 senators in a preliminary vote to get debate started but could only muster backing from 51 as just two Republicans crossed the aisle.

Reproductive rights have been an effective political cudgel for Democrats in the two years since the conservative-leaning Supreme Court overturned Roe v. Wade, the landmark 1973 decision that made abortion a constitutionally protected right.

The court had been bolstered by three judges appointed by Republican former president and current candidate Donald Trump, who recently suggested he was open to restricting access to contraception before walking back the remarks.

"Americans' uncertainty about using birth control is one of the many shameful consequences of overturning Roe v. Wade," said Schumer. "This is the mess Donald Trump and the MAGA Supreme Court... have created."

The Democrats face an uphill struggle to hang on to their majority in the upper chamber of Congress.

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Schumer has been introducing "messaging bills" – legislation that has little chance of becoming law but plants a flag on the party's policy positions – to boost members with tight re-election races.

In May, he introduced a tough border security bill that had no chance of getting Republican votes – giving Democrats in conservative states the opportunity to argue that they are tougher on immigration than their opponents.

And he has more floor action on reproductive rights penciled in, with a vote expected on legislation protecting in vitro fertilization later in June – although Republicans dismiss the drive as a political stunt.

"Contraception is available in every state in America, and there's no legitimate effort to change that," said Republican Senator Tommy Tuberville of Alabama.

"Democrats are using their powers as the majority party to engage in fearmongering to further their own political agenda."