'September earthquake': Expert warns Trump's sentencing delay could hugely backfire on him

Former President Donald Trump's pushback of his sentencing date in Manhattan is probably going to turn out badly for him, one expert told Newsweek.

New York Judge Juan Merchan on Wednesday ruled that the sentencing for Trump's 34-count felony conviction in the Manhattan hush money case will be moved from July 11, just days before the start of the Republican National Convention, to September 18.

The change was made after the Supreme Court's ruling that presidents have a presumption of immunity for official acts, Trump's lawyers moved to disqualify the conviction on the grounds that it was at least partially based on evidence obtained through acts when Trump was in office.

Ultimately, experts believe that it's unlikely Trump will prevail in getting the case tossed — and the bigger worry for him, University of Surrey political science professor Mark Shanahan told Newsweek, is that the delay itself is going to maximize the political impact of his sentence, triggering what he called a "September earthquake" right around when early voting starts in many states.

"Everyone was taken aback by SCOTUS's decision on presidential immunity, and all sides are scrambling to understand if and how it applies to the New York verdicts," said Shanahan.

READ MORE: Trump hush money sentencing delayed after Supreme Court ruling: report

"If the case gets tossed or, more likely, if the verdict gets postponed further, it will galvanize Democrats like no other cause with a likely strong ripple effect on the few undecideds in half a dozen states who will decide this election."

Nothing in this case will affect the vote of hardcore Trump supporters, Shanahan continued.

"But for voters who still believe in a constitutional separation of powers and rule of law, any further delay, or soft peddling on the New York verdicts, will light the fire on a final month of campaigning based on the premise of preserving democracy."

Other Trump cases already face a greater impact from the Supreme Court's decision, with the federal election conspiracy case set to be mired in hearings for months — although even if the trial can't take place before the election, these hearings might.