Earlier in the day, Johnson announced his resignation, stressing that he would continue to fulfill the role of party leader and prime minster until his successors are appointed.
"Note this follows the collapse of Macron's government in France as well as other EU countries. Many more will likely see changes ahead to include Germany and Italy," Rasmussen said.
He believes that all major Western leaders, including in the US, "need to be replaced" before the world will see "the potential for improvement."
Johnson’s resignation itself came as no surprise, according to the expert. "We also have seen diminishing support for Johnson's conservative party as well," he noted.
Rasmussen expressed overall concerns that the West is moving "on a very dangerous path" both economically and militarily.
"Fences will mend over time but not until western leaders are replaced with those that care for their own people and countries and respect all countries' sovereignty. We are moving in uncharted waters and the next several years will be challenging but there is still hope for a brighter future for all," he said.
Last week, Christopher Pincher resigned as deputy chief whip of the UK's Conservative Party after being accused of sexual misconduct in one of London's private members club. A number of politicians claimed that Johnson appointed Pincher to the post despite knowing about sexual misconduct allegations. On Tuesday, Johnson apologized and admitted, "in hindsight it was the wrong thing to do."
The scandal has led to a string of resignations, with dozens of officials stepping down from Johnson's government, including such key figures as Health Secretary Sajid Javid and Chancellor of the Exchequer Rishi Sunak.