Live updates: GOP kicks off first-ever midterm convention

GRAPEVINE, Texas -- Down the road from the GOP midterm convention in Dallas, Mike Njenga's trucking company is struggling. His diesel fuel expenses have skyrocketed because of the Iran war -- forcing him to take trucks off the road and pass price hikes to customers.

Njenga voted for Trump and has been happy to back Republicans for years. But he told ABC News' Rachel Scott he is strongly considering voting for Democrat James Talarico for Senate in November.

"Whether he's conservative, whether you're liberal, at this point, all I care [about] is economics," he said. "I want to make sure things I can survive in business. I want to make sure I'm going to be able to feed my kids."

Njenga's situation underscores the challenge Republicans face as they try to excite their base heading into the fall, and how Trump's handling of the economy and Iran war loom over all other issues.

Asked how he thinks Trump is handling the economy, Njenga replied, "Just looking at what is going on right now in the world and between the tariffs and the war in Iran, it's not very encouraging. I am disappointed."

-ABC News' Benjamin Siegel

People have dubbed the midterm convention the "Trumpapalooza" as the president is expected to be at the center of the celebration.

So far, it looks like it -- photos of Trump line the walls at the American Airlines Center.

-ABC News' Hannah Demissie

Trump said he anticipates a "tremendous crowd" at the convention but said some Republicans aren't coming due to a lack of space.

"I think we're going to have a tremendous crowd tonight. Sold out. Looks very big. Looks very exciting, and we're going to explain what we've done," Trump said as he was departing Joint Base Andrews for Dallas.

Asked by ABC's Mary Bruce about Republicans in key races who decided not to attend the convention, Trump said that "everybody is coming."

Trump argued that some people were not coming because there wasn't space, saying "we don't have room for 500 politicians."

"We have room for the ones that have a close race if they're slightly behind or slightly ahead or tied, but we don't have rooms for people that are 35 points up and don't need to be there," Trump said.

American Airlines Center in Dallas, where the convention is being held, can hold up to 20,000 people, according to American Airlines.

-ABC News' Isabella Murray and Nicholas Kerr

On the first day of the Republican's Midterm Convention, billionaire Democratic Illinois Gov. JB Pritzker, who is widely seen as a potential 2028 contender, held a press conference with Texas Democrats, where he argued this week’s events at the convention are serving as a distraction from the kitchen-table problems Americans are enduring.

"Donald Trump is hoping that a flashy primetime event will make you forget that well, his trade war is killing costs for families at the grocery store, his war in Iran is killing ranchers and farmers and their way of life,” Pritzker said.

As Democrats work to build a contrast to the Republican agenda throughout the Trump administration, Pritzker highlighted the unprecedented mid-century redistricting fight Texas Democrats endured last year, when many left the state to prevent a vote on new congressional maps in the state.

"In this moment, when America needs a new generation of leaders, fighters willing to stand up against tyranny, Texas Democrats have stepped into the breach. They alerted the nation to these dangers, and Texas Democrats set an example for the rest of America," he said.

Pritzker, who is running for reelection, punted when asked about his 2028 ambitions, but said, "anybody that is showing up here and bootlicking Donald Trump, and that's what this is all about, is probably going to be disqualified in 2028." Pritzker has not ruled out a presidential bid in 2028.

-ABC News' Juhi Doshi and Lalee Ibssa