HARRISBURG, Pa. (AP) — Democrat Joe Biden has been certified as the winner of the presidential election in Pennsylvania, culminating three weeks of vote counting and a string of failed legal challenges by President Donald Trump, state officials said Tuesday.

The Pennsylvania State Department “certified the results of the November 3 election in Pennsylvania for president and vice president of the United States,” Gov. Tom Wolf, a Democrat, tweeted.

“As required by federal law, I’ve signed the Certificate of Ascertainment for the slate of electors for Joe Biden and Kamala Harris," Wolf wrote.

The State Department said Wolf's “certificate of ascertainment” has been sent to the national archivist in Washington. Pennsylvania's electors, a mix of elected Democrats, party activists and other staunch Biden backers, will meet in the state Capitol on Dec. 14.

The results show Biden and Harris with 3.46 million votes, Trump and Vice President Mike Pence with 3.38 million, and Libertarian Jo Jorgensen with 79,000.

Secretary of State Kathy Boockvar, in a news release, called the state’s election officials and poll workers “the true heroes of our democracy.”

“We are tremendously grateful to all 67 counties who have been working extremely long hours to ensure that every qualified voter’s vote is counted safely and securely,” Boockvar said.

Trump, who lost the state’s 20 electoral votes to Biden, has made Pennsylvania a centerpiece of his unsuccessful legal attempts to invalidate the election results.

A federal judge on Saturday dealt a serious blow to the Trump campaign’s legal efforts by dismissing a lawsuit he said lacked evidence and offered “strained legal arguments without merit and speculative accusations.”