Democrats are growing impatient about the conditions — not to mention, the politics — along the U.S.-Mexico border, and Homeland Security Secretary Alejandro Mayorkas could bear the brunt when he testifies in the House on Wednesday.

What we're hearing: Rep. Bennie Thompson, chair of the Homeland Security Committee, may have a handful of pointed questions. Some Texas Democrats also remain peeved they didn't get any warning a White House delegation would be visiting their state two weeks ago — aggravating potential allies.

• To date, Republicans have led the criticism of the Biden administration, but that's becoming politically untenable for the president's own party.
• "I think it’s safe to say Secretary Mayorkas’ concerning rhetoric on immigration and President Biden’s questionable decision to rescind successful programs and agreements will be hot-button issues,” Rep. Michael McCaul (R-Texas), a former chair of the committee, told Axios.
• Thompson was more reserved ahead of the hearing: “I look forward to Secretary Mayorkas' testimony."
• Rep. Veronica Escobar (D-Texas), who represents El Paso, told Axios she has been invited to be a special guest questioner.

The big picture: Facing a surge of migrants — including unaccompanied minors and families with young children — some Biden officials are privately concerned Mayorkas won’t be able to defend a border situation that is, in part, out of the president's control.

• Mayorkas attempted to defuse the situation Tuesday, releasing a lengthy statement addressing each potential point of concern from the committee.
• He even gave a preemptive headline: The U.S. is on pace to encounter more people at the U.S.-Mexico border "than we have in the last 20 years," he wrote.
• Mayorkas also acknowledged the surge of migrants is "difficult" while adding the administration is "making progress and we are executing on our plan."

Driving the news: While White House press secretary Jen Psaki has said "now" is not the time to come, Biden has repeatedly vowed a more humane approach to immigration control than former President Donald Trump.

• Republicans have seized upon the increased arrivals to attack the White House and accuse Biden of pursuing an open border policy.
• House Minority Leader Kevin McCarthy led a delegation of Republicans to Texas on Monday. Democrats also planned their own trip.
• Trump also attacked Biden for the problem during his first speech since leaving office.

For its part, the White House is eager to get Xavier Becerra confirmed as secretary of Health and Human Services and start filling out key border staff throughout the government.

• HHS plays a crucial role in sheltering minors once they have been discharged from Customs and Border Patrol.

What we are watching: Will committee Democrats use their questions to engage Mayorkas on the border, or will they stick to the general plan to focus on Jan. 6 and domestic terrorism.