Spaht was urged to run for governor to succeed the then term-limited Earl Kemp Long. In the runoff election, anti-Long elements, including the third- and fourth-placed primary candidates, Hale Boggs and James M. McLemore coalesced behind Kennon. Even Bill Dodd, the outgoing lieutenant governor who fared poorly in the gubernatorial primary, endorsed Kennon, much to the chagrin of Earl Long, who was said to have hand-picked Spaht so that Long might still exert some influence in future government decisions. Dubbed "Earl's Boy", Spaht was the Long candidate largely by default in what became a strongly anti-Long year. Opponents of the Long ticket opposed tax increases during Earl Long's tenure and feared such increased costs of government would continue under a Spaht administration. In the first primary on January 15, 1952, nine candidates ran. Spaht led with 173,987 votes to Kennon's 163,434 votes. In the runoff, all seven other candidates, including U.S. Representative Hale Boggs of New Orleans, endorsed Kennon. With 48 percent turnout, Kennon defeated Spaht 482,302 to 302,653. In the April 22general election, Kennon defeated, 96–4 percent, only the second Republican of the twentieth century to seek the state governorship, Harrison Bagwell, a Baton Rouge attorney.
Supporting Nixon/Lodge ticket
In 1960, Judge Spaht refused to endorse the Kennedy/Johnson presidential ticket, which handily secured the ten electoral votes of Louisiana, having benefited from divided opposition. Instead, Spaht gave speeches for the Nixon/Lodge Republican team. In Minden, Kennon's hometown, Spaht spoke at the invitation of the local "Democrats-for-Nixon" committee. Earl Long had endorsed the Kennedy-Johnson slate but had died two months before the general election. Spaht declared that the Kennedy record was one of "extreme socialism in matters of health, education, and taxes." Spaht said the Kennedy position on offshore tidelands was contrary to the needs of Louisiana state government. He claimed that only Nixon could "stand up" to the Soviets. "The best way to determine what a man will do is to see what he already has done," said Spaht in endorsing Nixon. Spaht's visit to Minden was arranged by the Democratic StateCentral Committee member and dairyman Roy D. "Don" Hinton, who said that his opposition to the Kennedy/Johnson ticket grew after he attended a state party meeting in Baton Rouge, where more details of the Democratic national platform were unveiled.
Spaht died in Baton Rouge and is interred at Greenoaks Memorial Park in East Baton Rouge Parish. Spaht's son, Carlos G. Spaht, II, who is registered with no party, is a mathematics professor at Louisiana State University in Shreveport. Another son, Paul H. Spaht, a Republican, practices law at his father's former Baton Rouge firm. On April 2, 2008, Spaht, former state senator J. D. DeBlieux, and former Register of the State Lands Ellen Bryan Moore, were honored posthumously by the annual Louisiana Governor's Prayer Breakfast.