“We are all in,” Sen. Ted Cruz (R-TX) told a packed room of California Republicans on Saturday afternoon, vowing to stop frontrunner Donald Trump in the state on June 7.

“We are going to be competing for all of 172 delegates in California in all 53 congressional districts. It is going to be a battle on the ground, district, by district, by district.”

Cruz spoke the day after Trump and Ohio Gov. John Kasich addressed the convention. With or without a strong performance in Indiana, a decisive stand in California could help him prevent Trump from achieving a 1,237-delegate overall majority — and move the Republican National Convention to a second ballot in July.

“California is at a crossroads. California is going to decide this Republican primary. Who’d a thunk it? Year after year y’all are used to being treated by Republicans like an ATM, to take your money and spend it in other states. Well I can tell you right now, we’re going to spend more money in California than we raise in California.

“But for any of you that have your checkbooks handy I would be glad for you to prove me wrong,” he added, jokingly.

Cruz commented that he has frequently heard the question about why he named Carly Fiorina as his running mate so early in the presidential race. He declared that Fiorina would be the “first Californian on a national ticket since Ronald Reagan.”

Describing his reason for the early pick Cruz said, “I believe the people of California and the people of this country deserve a clear and simple choice. Elections are about choices, and I think the contrast could not be clearer between Carly and me — the one side, a positive, optimistic, forward looking, conservative campaign based on real policy solutions to the challenges facing this country, versus on the other side, Hillary Clinton and Donald Trump. And Hillary Clinton and Donald Trump are flip sides of the same coin.”

Cruz’s father Rafael spoke to Republicans at the San Bernardino Republican Party Central Committee meeting on Thursday, calling the Cruz-Fiorina ticket a “a California-Texas ticket.” Every successful Republican presidential candidate since Calvin Coolidge has had a connection to either state.

Fiorina ran for U.S. Senate in California in 2010, winning the Republican nomination, but losing in the blue state to incumbent Democrat Sen. Barbara Boxer.

Cruz brought up news that he had released earlier that day detailing Trump donations to liberal California Democrat politicians Gov. Jerry Brown, Lt. Gov. Gavin Newsom and California Attorney Gen. Kamala Harris. “Now y’all are experiencing first hand the consequences of those misguided liberal policies.”

Speaking of his father’s journey from Cuba to America and the American values of freedom and opportunity, Cruz added: “That’s the mighty California spirit that built this state into such an incredible economic engine, that you have survived and thrived in the face of Democratic mismanagement year after year after year.”

California holds its primary election on June 7. Vote-by-mail ballots are sent out in the weeks leading up to that date, starting May 9. Trump, Kasich and Cruz each held additional events during their time in the state before returning east. The Indiana primary is Tuesday, May 3.

Follow Michelle Moons on Twitter @MichelleDiana