Within four months, the mother and partner of Brian D. Sicknick made two visits to the Capitol — for a February memorial service to honor the deceased officer after the violent siege of Jan. 6 and Thursday to plead with Republican senators to support an independent investigation into the failed insurrection by a pro-Trump mob.

But the day of meetings and calls by Gladys Sicknick and Sandra Garza, the late officer’s companion of 11 years, with 16 senators and their staffs appeared unlikely to change hearts and minds in the GOP.

Republicans were poised to block legislation to create a bipartisan commission that would examine the events of that day — the worst attack on the Capitol since the War of 1812. Senate Minority Leader Mitch McConnell (R-Ky.) said Thursday that the probe was “extraneous” and would not shed light on what happened Jan. 6, while others in the GOP saw it as a Democratic-driven, endless pursuit of former president Donald Trump.

Gladys Sicknick said Thursday morning that it has angered her to see Republican senators oppose the commission.

“That’s why I’m here today,” she told reporters. “You know, usually I stay in the background, and I just couldn’t — I couldn’t stay quiet anymore.”

Garza said it was “very disturbing” that some members of Congress seem uninterested in finding answers to the still-lingering questions around the attack.

“I mean, why would they not want to get to the bottom of such horrific violence?” Garza said. “They are here today — and with their families and comfortable — because of the actions of law enforcement that day. . . . It just boggles my mind.”

Two officers — D.C. police’s Michael Fanone and the U.S. Capitol Police’s Harry Dunn — who responded that day and protected members of Congress joined Sicknick and Garza in trying to persuade Republicans.

The face-to-face meetings involving Brian Sicknick’s family, the officers and Republican senators highlighted a stark choice for GOP lawmakers: either stand with Trump, who opposes the commission, or support members of law enforcement.

Sicknick suffered two strokes and died of natural causes a day after he confronted rioters at the insurrection, the District’s chief medical examiner ruled last month. In early February, Sicknick, who grew up in New Jersey, was honored at the U.S. Capitol, with President Biden, Vice President Harris and congressional leaders paying their respects. His remains were interred at Arlington National Cemetery.

Nearly 140 officers were assaulted during the attack, as they faced rioters armed with ax handles, bats, metal batons, wooden poles, hockey sticks and other weapons, authorities said.

The House last week passed legislation that would form an independent commission to investigate the Jan. 6 riot, with 35 Republicans joining all Democrats in supporting the measure. The vote in the Senate may occur on Friday.

Gladys Sicknick, Garza, Dunn and Fanone started their day early on Capitol Hill, beginning with a meeting with Sen. Mitt Romney (R-Utah), who supports the commission.

By day’s end, the group had met in person with more than a dozen Republican senators. They also lobbied some senators by phone and met with staffers for others, including a scheduled session with aides to McConnell.

Former congresswoman Barbara Comstock (R-Va.) accompanied the group during their visit to Capitol Hill.

“If January 6th didn’t happen, Brian would still be here. Plain and simple,” Dunn told reporters Thursday morning ahead of the long day of meetings.

Late Thursday night, Sen. Lisa Murkowski (R-Alaska), one of the few Republicans who has said she would support the commission, recounted her conversation with Brian Sicknick’s mother earlier that day.

“I’m heartsick that you feel you need to advocate to members of Congress that we stand up and say the truth is hard but the truth is necessary,” Murkowski said she told her.

Democrats would need at least 10 Republicans to join them in supporting the measure for it to pass, but Republicans were lining up behind McConnell in opposition.

“I do not believe the additional, extraneous ‘commission’ that Democratic leaders want would uncover crucial new facts or promote healing,” McConnell said in floor remarks. “Frankly, I do not believe it is even designed to.”

McConnell had praised Brian Sicknick in a Senate floor speech in February.

“The Senate and the entire country send our deepest condolences to Officer Sicknick’s family and all who loved him,” he said on the same day that Sicknick was lying in honor at the Capitol. “His name will never be forgotten.”

The White House has repeatedly urged Congress to approve the legislation.

Several Republican lawmakers have sought in recent days to play down the seriousness of the Jan. 6 attack, comparing some in the violent mob to “tourists,” railing against law enforcement for seeking to arrest them and questioning how anyone could be sure the rioters were supporters of Trump.

Garza pushed back against those efforts, telling reporters that the message for Republican senators who are on the fence is, “Facts are facts.”

“If they look at the footage that happened, it’s very obvious that was not a peaceful day,” Garza said. “Police officers were getting attacked, fire extinguishers were being thrown at them, they were being attacked by flagpoles. Officer Dunn here, Officer Fanone — they can basically tell you right now what they experienced, and it wasn’t a tourist day. It wasn’t tourists just passing and walking by.”

Sen. Ron Johnson (R-Wis.), meanwhile, said he continues to oppose the commission even after meeting with the group.

“Although we respectfully disagreed on the added value of the proposed commission, I did commit to doing everything I could to ensure all their questions will be answered,” Johnson said in a statement.

Johnson, a Trump ally, has been among the most vocal lawmakers in pushing false and misleading accounts of the Capitol riot. He also last month sent a letter to U.S. Capitol Police questioning the department’s earlier statement that Sicknick died from “injuries sustained while on-duty.”

In a statement Thursday morning, Sen. Joe Manchin III (D-W.Va.) lashed out at McConnell and any other Republican who opposes the independent commission, accusing them of taking a “political position” and fearing the truth.

“There is no excuse for any Republican to vote against this commission since Democrats have agreed to everything they asked for,” Manchin said.

“Mitch McConnell has made this his political position, thinking it will help his 2022 election,” Manchin added. “They do not believe the truth will set you free, so they continue to live in fear.”

While Democrats hold the majority in the Senate, several in their ranks, including Manchin, oppose eliminating the filibuster rule that would allow the party to push through its priorities, including establishment of the commission.

This week, Sen. Susan Collins (R-Maine), a moderate who has expressed willingness to vote for a commission, began circulating an amendment to build GOP support for the bill. But it remains unclear whether her proposed changes would be enough to bring the Republican senators needed on board — or even whether Democrats would accept the amendment.

Some former members of Congress have been urging those currently in the Senate to approve the establishment of a commission.

“History is going to reflect on this day pretty clearly,” former senator Chuck Hagel, a Republican from Nebraska who also served as President Barack Obama’s secretary of defense, said on a call with reporters organized by the group Issue One.

“Not to have the Congress involved and do something and respond to this is going to be a terrible black mark on the Congress of the United States,” Hagel said, adding: “As a former member of the Senate, I wouldn’t want to have to live with that.”