Washington (AFP) – The US Senate on Tuesday confirmed the 100th federal judge appointed by President Joe Biden, as he works to dilute the impact his predecessor Donald Trump had on the courts.

Under the US Constitution, presidents appoint Supreme Court justices and federal judges for life, with Congress' upper chamber confirming or rejecting the nominee.

In theory, judges are politically impartial, but their previous legal decisions and the president who appointed them generally shed some light on their beliefs and leanings.

Gina Mendez-Miro, a 49-year-old lawyer, became the latest judge confirmed to the US Federal Court for the District of Puerto Rico, after a 54-45 vote Tuesday in the Senate.

Because Democrats have controlled the Senate throughout Biden's presidency, he has been able to vet nominees like Mendez-Miro at an accelerated pace.

In an effort to increase diversity in the judiciary, Biden has put forth candidates with traditionally underrepresented backgrounds: three quarters have been women and only one-third have been white, according to the American Constitution Society.

He additionally nominated Ketanji Brown Jackson to the US Supreme Court, marking the first time a Black woman was named to the bench.

Mendez-Miro will be the first openly LGBTQ judge to serve on her court, Biden said in a statement.

“I'm especially proud that the nominees I have put forward… represent the diversity that is one of our best assets as a nation,” the president said.

Biden celebrated the milestone of 100 confirmed judges as a “profound moment” that highlights his administration's productivity. Two more of his picks for judge were confirmed by the Senate later in the day.

“We have made important progress in ensuring that the federal judiciary not only looks more like the nation as a whole, but also includes judges from professional backgrounds that have been historically underrepresented on the bench,” Biden said.

White men

The diversity push is a complete reversal from Trump's four-year presidency: The Republican appointed more than 230 judges to the federal courts, three-quarters of whom were men and 85 percent of whom were white.

And his criteria differed from Biden: To please his base, Trump promised to choose judges who opposed abortion, supported carrying firearms and defended religious freedoms.

The 45th president left a lasting mark on the judiciary, particularly the Supreme Court, where he appointed three of its nine justices, steering the court clearly to the right.

In June the reshaped Supreme Court overturned the national right to an abortion, expanded gun rights and limited the government's ability to fight global warming.

Determined to counter the US judiciary's sudden tack to the right, Biden is moving quickly — with 50 more federal judge nominees awaiting confirmation.

To help assure their replacements are appointed while a Democrat is president, several liberal-leaning judges have either retired or “taken senior status” — a process by which their seat is vacated and they have the option to handle a lighter caseload.

‘Judicial shopping'

Although Biden rivals Trump's pace, his appointments will not have the same overall impact. Trump was able to largely replace judges appointed by Democratic presidents, changing the political tilt of the courts.

Under Trump, three of the 13 influential federal courts of appeals were flipped to Republican-leaning majorities.

Biden is in the process of flipping only one such court.

Trump was able to achieve maximum impact with the help of then Senate majority leader Mitch McConnell, who laid the groundwork for the effort in the last two years of Barack Obama's presidency.

After Republicans regained Senate control in 2014, McConnell blocked most judges appointed by the Democratic president, including a Supreme Court candidate.

So 100 federal judiciary judgeships remained open when Trump entered the White House.

Such political games have undermined the courts' image of impartiality and reinforced “judicial shopping,” which refers to strategically filing a case in a specific court that a lawyer knows will be sympathetic to a given cause.

Abortion opponents, for example, recently filed a suit against abortion pills in Amarillo, Texas where the only federal judge, a Trump appointee, is known for ultra-conservative views.