After Sen. John Cornyn said he didn't know Rep. Joaquin Castro "very well," the congressman insisted that he had reached out to the senator on his resolution to overturn President Donald Trump's national emergency declaration. | Chip Somodevilla/Getty Images Congress Rep. Castro jabs at Cornyn ahead of possible Senate showdown

Rep. Joaquin Castro said Monday that his phone calls to Sen. John Cornyn on legislation to block the government seizure of Texans' land went unreturned, countering the Texas senator's claim that the two lawmakers and potential 2020 Senate race rivals had never worked together.

"@JohnCornyn - I’m the one who called you last week to ask you to vote for my bill against giving away hundreds of miles of Texas land to the federal government in a Washington power grab," Castro (D-Texas) wrote in the tweet. "You never called me back. I don’t feel bad though; I hear it happens to lots of Texans."


The retort came after Cornyn, a Republican, said on Monday that he didn't know Castro "very well" when asked about the Texas congressman's anticipated run to unseat him in next year's Texas Senate race.

"I really don’t know Congressman Castro very well. I’ve worked with virtually everybody else in the Texas congressional delegation but never had the occasion to work with him to my recollection," Cornyn told San Antonio-based KTSA News. The four-term Texas congressman went on to retweet several accounts of Cornyn not responding to constituents.

Castro, replying to a tweet with that quote, insisted that he had reached out to Cornyn last week on his resolution to overturn President Trump's national emergency declaration, a move intended to allow for the construction of a wall along the U.S.-Mexico border. Such a project already faces opposition from Texas landowners whose property would be seized by the president's controversial border security measure.

Sign up here for POLITICO Huddle A daily play-by-play of congressional news in your inbox. Email Sign Up By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

A resolution blocking the emergency declaration, introduced by Castro, was vetoed by the president last week. It had passed both the House and the Senate on bipartisan votes.

Castro, whose twin brother is running for president, has been among the most discussed potential challengers to Cornyn, who until last year was the number two Republican in Senate leadership. The congressman's campaign adviser Matt Jones told Texas Monthly last week that “we’ll be making an announcement in the very near future."

In his radio interview, Cornyn characterized Castro as too liberal for Texas, claiming he's further to the left than former Rep. Beto O'Rourke, the El Paso Democrat who nearly bested Sen. Ted Cruz (R-Texas) in last year's midterm elections. O'Rourke, who has voted as a moderate Democrat, announced last week that he is running for president.

Cornyn, seen by some as potentially vulnerable in a presidential election year after Cruz was nearly unseated in 2018, is likely to be a formidable candidate for reelection in deep red Texas. He is a far less polarizing figure on the national stafe than Cruz and already has more campaign cash than any other senator, with $5.8 million in the bank.

"It's a free country. People can run, but I happen to think that somebody who votes 97 percent of the time with Nancy Pelosi is not going to do very well in Texas," Cornyn said. "Texas has Democrats, Republicans and independents, but Congressman Castro, he votes to the left of Beto O'Rourke."

"I just don't think it's going to work," he said.