WASHINGTON (NewsNation Now) — President Donald Trump Thursday intensified his effort to challenge the results of the election, sending his lawyer out to argue that widespread fraud is the reason he lost, and inviting Republican lawmakers from a state he is contesting to a meeting at the White House Friday.

But alleging fraud is different from proving it. There has been no evidence of widespread election fraud in any state, according to officials at both the state and federal levels. In addition, a series of cases filed by the Trump campaign have been dismissed for lack of evidence.

Trump campaign lawyers held a news conference Thursday afternoon in Washington. Rudy Giuliani and campaign legal advisor Jenna Ellis led the conference. You can watch the news conference in the player below.

Giuliani told reporters there is abundant evidence of voter fraud in states Trump lost, like Michigan.

“Do you know how many affidavits we have in the Michigan case? 220 affidavits.,” Guiliani said in part. “Those are people who give affidavits, report an incident that under any other circumstances would have been on the front page of all your newspapers if it didn’t involve the hatred that you have, irrational, pathological hatred that you have for the president.”

On Pennsylvania, Guiliani offered more of the same.

“In Pennsylvania, the margin of victory now for Biden – which is not a victory. It’s a fraud,” he said.

Thursday in Wilmington, the President-elect reacted to the White House news.

“What the President is doing now is really, um,…it is going to be another incident where he will go down in history as being one of the most irresponsible presidents in American history. It’s not even in the norm. There’s questions if it is even legal,” Biden said.

Here’s a look at where Republican election challenges stand in six states:

ARIZONA

THE CASE: The Arizona Republican Party is trying to block the certification of the election results in the state’s most populous county, Maricopa, until the court rules on the party’s lawsuit asking for a new hand count of a sampling of ballots. An audit already completed by the county found no discrepancies, officials said.

WHAT HAPPENED: A hearing in the case was held Wednesday. Arizona judge John R. Hannah Jr. rejected on Thursday Nov. 19 the state Republican lawsuit requesting additional Maricopa County vote audit. The certification deadline for Maricopa County is Nov. 23.

In a separate case, Trump’s campaign and the Republican National Committee had sought to delay the certification of election results in Maricopa County. Republicans asked for the manual inspection of ballots in metro Phoenix, alleging that some votes were improperly rejected. A judge dismissed the case on Nov. 13 after the campaign’s lawyers acknowledged the small number of ballots at issue wouldn’t change the outcome of how Arizona voted for president.

GEORGIA

THE CASE: Attorney, L. Lin Wood Jr. has sued in an attempt to block the certification of election results in Georgia. Wood alleges Georgia illegally changed the process for handling absentee ballots. Wood’s lawsuit takes aim at a legal settlement signed earlier this year that addresses accusations about a lack of statewide standards for judging signatures on absentee ballot envelopes. Georgia’s deputy secretary of state has called Wood’s case a “silly, baseless claim.”

WHAT HAPPENED: The governor and the top election officials certified results in that state on Nov. 20 and Biden won the 16 electoral votes from Georgia, the final results showed Biden leading by a margin of 12,670 votes or a quarter of a percent because that victory is by less than half of one percent. President Trump can request a recount his campaign has 2 business

MICHIGAN

THE CASE: Trump’s campaign is trying to block the certification of election results in the state, alleging that election officials “allowed fraud and incompetence to corrupt the conduct of the 2020 general election.” Trump’s legal team alleges that their observers were prevented from being able to properly watch the vote counting, that ineligible ballots were counted and that Republican challenges to ballots were ignored.

Another lawsuit filed this week on behalf of two poll challengers asks a court to halt the certification of election results until an independent audit is completed to “ensure the accuracy and integrity of the election.”

WHAT HAPPENED: The Trump campaign dropped its case on Thursday, citing statements from Republican Wayne County canvassers who initially blocked certification of election results in Michigan’s largest county before approving them on Tuesday. The two canvassers now say they want to change their position again, but officials say there’s no way for them to rescind their vote.

NEVADA

THE CASE: Trump’s campaign is asking a judge to nullify Nevada’s election results or set them aside and declare him the winner, arguing that illegal or improper votes were cast and the use of optical scanning to process signatures on mail-in ballots violated state law. The Trump lawsuit, filed Tuesday, rehashes arguments that judges in Nevada and elsewhere have already rejected. It claims that votes were cast on behalf of dead people, that election observers weren’t allowed to witness “key points” of processing and that people on American Indian territories were illegally given incentives to vote.

In a separate court filing this week, a voting watchdog group led by a conservative former state lawmaker wants a judge to block statewide certification of the election.

WHAT HAPPENED: The Maricopa County board of supervisors certified their general election results Nov. 20. The board members said that all ballots cast in the county are accounted for and every valid vote will be in the final election results. Once the rest of the secretary of state and governor will make the final certification of Arizona’s 11 electoral votes to Joe Biden.

PENNSYLVANIA

THE CASE: A Trump campaign case aims to stop the state from certifying the election, alleging Philadelphia and six counties wrongly allowed voters to correct problems with mail-in ballots that were otherwise going to be disqualified for a technicality, like lacking a secrecy envelope or a signature. The total number of affected ballots was not expected to come anywhere close to Biden’s margin of more than 80,000 votes.

WHAT HAPPENED: Trump’s personal lawyer, Rudy Giuliani, signed onto the case this week after others abruptly withdrew, and the former New York City mayor argued in court on Tuesday for the first time since the 1990s. The judge did not immediately issue a ruling and canceled a hearing that was set for Thursday but set out a schedule for both sides to make new filings this week.

WISCONSIN

THE CASE: Trump’s campaign on Wednesday filed for a recount in the counties that cover Milwaukee and Madison, both Democratic strongholds. It alleged — without evidence — that absentee ballots were illegally altered or issued and that government officials violated state law.

WHAT HAPPENED: Biden leads Trump by 20,000 votes statewide. The recount requested by Trump will begin Friday and has to be complete by Dec. 1, the deadline for the vote to be certified at the state level. Milwaukee county officials say they expect to have their results by Nov. 25. State and local elections officials reiterated that there was no evidence to back up the claims Trump was making. Trump paid $3 million for the partial recount of the state.

Associated Press reporters Alanna Durkin Richer and Nomaan Merchant and writers Jacques Billeaud in Phoenix, Marc Levy in Harrisburg, Pa., Ken Ritter in Las Vegas, Kate Brumback in Atlanta and Scott Bauer in Madison, Wis., contributed to this report.