I’m in Dhaka at the moment and have taken the opportunity to learn a bit about the creation of Bangladesh and the preceding war. I’m curious what US attitudes were like at that time. Did the US ever consider involving itself? Was there any push to do so among US citizens or were people too focused (and tired of) involvement in Vietnam?
I seem to be tackling modern South Asian questions this week!
Let me start by addressing the first part of the question. The US government did seriously consider involvement in the 1971 Bangladesh crisis - on behalf of Pakistan.
In order to understand this, it helps to examine the geopolitics of 1971. Pakistan was a US ally, and member of two US-led military alliances, the Central Treaty Organization (CENTO, sometimes also called the Baghdad Pact), and the South East Asian Treaty Organization (SEATO). In addition to being part of the United States' worldwide anti-Soviet alliance system, the head of Pakistan's military junta, Yahya Khan, was on good personal terms with President Richard Nixon (he was the intermediary between Nixon and Mao in Nixon's bid to re-establish US-Chinese relations).
In contrast, India, although nominally a non-aligned country, was on very friendly terms with the Soviet Union (India had actually signed a friendship treaty with the USSR in August of 1971). Nixon and his National Security Advisor Henry Kissinger were very concerned that strengthened Soviet-Indian ties would spoil "“everything we have done with China” - Nixon on July 15 had publicly announced his official visit to China that was to take place the following year.
In addition to the geopolitics, part of what must be acknowledged in understanding Nixon and Kissinger's response to the Bangladesh crisis was their deep hatred of Indian figures such as Indira Gandhi (whom is referred to numerous times in Nixon's Oval Office recordings as "the bitch" among other epithets), Indians ("a slippery, treacherous people", "what they really need is ... a mass famine"), and South Asians in general ("“Biafra stirred up a few Catholics. But you know, I think Biafra stirred people up more than Pakistan, because Pakistan they’re just a bunch of brown goddamn Moslems.”). Nixon and Kissinger were frankly interested in projecting a "tough" image for the US to reinforce their realpolitik (and to ideally win them an extrication from South Vietnam on favorable terms), and not interested at all in any humanitarian concerns. If anything the Nixon administration turned what was essentially a regional conflict into a global geopolitical crisis in order to project an image of US toughness (an NSC aide wrote that the image projection was to impress on Chinese leaders that the US "was a reliable country to deal with").
As such, the US continued to ship arms to Pakistan during the conflict, threatened to cancel upcoming US-Soviet summits if the USSR did not stop providing arms to India, and dispatched the aircraft carrier USS Enterprise along with three escort vessels to the Bay of Bengal in order to deter Indian attacks on Pakistani forces in East Pakistan/Bangladesh. Ultimately the Indo-Pakistan War was ignited when Pakistani forces attacked Indian forces.
Something to think about for context- there was only the network and local evening news and newspapers at the time, and the Vietnam War, Cambodia and Laos, the 26th Amendment, shool busing in the Supreme Court, the Pentagon Papers and Daniel Ellsberg, the Aattica prison riots, the Sylmar earthquake, and so on were all competing for space and attention in the national news. The idea that the general public of the US might have a strong opinion would require this story to be much more than the "page 6 in the Des Moines Register" type of story many editors would relegate such things to.
Again, this is about context. The war in East Pakistan/Bangladesh is today recorded as a major event in South Asia in 1971, but at the time there were many many bigger stories making headlines in the US.