Specific links between political parties and religious groups are outlawed by the constitution, and the situation is now raising fresh questions about the country's future at a crucial point on Myanmar's journey from military dictatorship to a functioning democracy.
"The trend is like a mix of religion and politics," Bo told ucanews.com in an interview at his Yangon residence.
His chief concern is the emergence of the hard-line Buddhist monk movement, the Association for the Protection of Race and Religion, commonly known as Ma Ba Tha. The group was formalized in 2014 following two years during which the country's minority Muslims, who account for about seven per cent of the country's 50 million people, found themselves under attack in deadly violence that the monks helped ferment.
The movement has taken on a tone that is Buddhist nationalist and overtly anti-Muslim. Some senior members of the movement have given personal endorsements to President Thein Sein, who is seeking a second five-year term.
While the power of such backing can only be measured at the ballot box, the group's growing influence is undeniable.
It was Ma Ba Tha that successfully lobbied the government for the introduction of four race and religion laws that opposition parties and international observers have condemned as discriminatory. The clerics had argued that Myanmar's Buddhist identity was at risk, claiming a growing but unspecified influence by the Muslim minority.
Critics say the race and religion laws are squarely aimed at the nation's one million or so ethnic Rohingya people. The regulations impose mandatory "birth spacing" for women; Buddhist women must register their marriages in advance if marrying a man outside their faith; and restrictions on religious conversions have been enshrined in legislation.
Ma Ba Tha's September "victory" celebrations after the laws were enshrined have only increased perceptions of their political influence.
Yet for Bo, this was a disturbing display of "tribalism" in a country that teems with a multitude of languages, ethnicities and religions — although ethnic Bamar Buddhists represent the largest single group.
"The attitude that Myanmar must have one race and one religion, such as Bamar and Buddhist, is not acceptable," he warned.
Bo has been one of the rare voices with international heft in Myanmar to speak out against hate speech and religious discrimination. Many international rights groups had hoped such a role would naturally be taken up by Aung San Suu Kyi, the popular opposition leader and Nobel Peace Prize laureate. Yet she has been largely silent about widespread discrimination against Myanmar's Muslims — particularly the Rohingya community in tense Rakhine state, where violence in 2012 left scores dead and more than 150,000 people still trapped in internal refugee camps that they are forbidden, at gunpoint, to leave.
"Suu Kyi should speak out on the conflict in Kachin state and on Rohingya Muslims, who are confined to the camps," said Bo, who admitted he admires her personal integrity, fearlessness and passion.
In September, Bo issued an appeal denouncing the race and religion laws and demanding their repeal.
"Parliament was coerced by a fringe group of the religious elite to enact four black laws, fragmenting the dream of a united Myanmar," Bo wrote.
He said the compassionate teachings of Buddhism in Myanmar were being threatened by "peddlers of hatred."
In another message shortly after this, the cardinal urged all of Myanmar's citizens to vote. The message was framed as a guideline for selecting the best candidate.
While he was careful to avoid supporting any particular candidates or party, Bo listed attributes voters should look for when picking their choice at the ballot box.
These included an ability to work with "different ethnic groups and religions" and a willingness to safeguard the country's natural resources, rather than "selling our sacred rivers ... to foreign powers."
Bo told ucanews.com that he made his statements because Myanmar has reached a pivotal moment.
Ahead of the controversial religion laws being enacted, divisions were exacerbated when the government stripped about 800,000 Rohingya of "white cards" that previously handed them certain rights, include the right to vote. Then in September, the electoral commission disqualified the vast majority of Muslim candidates who had applied to run in the Nov. 8 election.
Such alienation, Bo said, comes at a crucial point in Myanmar's development.
"It's time to let a new system run the country, so I vehemently urge people to embrace the opportunity to vote for worthy candidates as a sacred duty," Bo said. "It's time to end old attitudes, old elites and the old system that has existed for five decades."
He cited comments from St. John Paul II, who said that "diversity is strength" — something that shouldn't be merely tolerated, but celebrated.
In December, the cardinal plans to return to his home village to celebrate his 25th year as bishop. There are Catholics in his village, of course, but also Buddhists.
"What I want to highlight is that Catholics and Buddhists in my native village have been living together as a harmonious society for centuries," the cardinal said. "That's the interreligious message that I want to share with the people of Myanmar."