Never heard of this "Manifest Destiny" thing before, so I clicked on the link that Joe Offer provided and found this:

There are three basic themes to manifest destiny:

The special virtues of the American people and their institutions
The mission of the United States to redeem and remake the west in the image of agrarian America
An irresistible destiny to accomplish this essential duty"

I think that that is clear enough as to who was doing what and to whom, and remembering just exactly when the bulk of this redeeming and remaking was taking place [i.e. In the mid-to-late 19th Century] I think any attempt at putting this down to the English takes a massive stretch of the imagination.

Influence in the American colonies? Take a look at some of the place names out to the West of what up until 1776 were British colonies. From the Canadian border right the way down to the Gulf Coast at New Orleans you will find a string of places with French names - they used to be trading posts and definitely pre-date Manifest Destiny and the War of Independence.

Detroit; St Clare; Fort Pontchartrain; Sandoski; Delaware; Augusta; Natchez; Lac Ponchartrain; New Orleans.

A string of trading posts that served to hem the settlers to the East in. British colonial settlers fought the French/Indian/Frontier War in the 1750s just to break out. But the British signed a Treaty with Tribes of the Five Nations that fully recognised THEIR rights to their lands in the Ohio and Wabash basins [British American Settlers did not like that at all]. A few years later and a change of sides the American colonists sided with the French in order to break that Treaty and they fought? Yep you've got it, The American War of Independence, and the American colonists expanded west, the one thing they were not was British, English or Scottish, for years they had been describing themselves as American colonists. And the track record of these Americans and all who followed after was that no treaty signed with them was worth the paper it was written on.

Now this is rather at odds with:

" I have no doubt that there were settlers in North America from most European ethnic groups from the 1600s, but the mass migration of working-class Europeans didn't happen until the middle to late 19th century, and people of English and Scottish ancestry were the center of political power in the US until well into the 20th century. Manifest Destiny was primarily a philosophy of Americans of English heritage. The Americas were conquered before most of our ancestors ever got here. Take a look at the list of signers of the Constitution - it's clear that the ruling ethnic group in the U.S. was English."

On migration to the USA:

During the 17th century, approximately 400,000 English people migrated to Colonial America. However, only half stayed permanently.

From 1700 to 1775 between 350-500,000 Europeans immigrated: the estimates vary in the sources. Only 52,000 English supposedly immigrated in the period 1701 to 1775. Taking the upper figure of 500,000 the rest, [400-450,000} were Scots, Scots-Irish from Ulster, Germans and Swiss, French Huguenots. In addition to these immigrants there was the involuntarily migration into America of 300,000 Africans. It should also be noted that over half of all European immigrants to Colonial America during the 17th and 18th centuries arrived as indentured servants [Slaves in all but name]. The European populations of the Middle Colonies of New York, New Jersey, Pennsylvania and Delaware were ethnically very mixed, the English constituting only 30% in Pennsylvania, 40-45% in New Jersey, to 18% in New York numbered 22,000.

The mid-19th century saw an influx mainly from northern Europe from the same major ethnic groups as for the Colonial Period but with large numbers of Catholic Irish and Scandinavians added to the mix; the late 19th and early 20th-century immigrants were mainly from Southern and Eastern Europe. Now Manifest Destiny without any doubt is from this period:

Manifest Destiny has been condemned as an ideology that was used to justify genocide against Indigenous Americans.

Historians have emphasized that "manifest destiny" was a contested concept — Democrats endorsed the idea but many prominent Americans (such as Abraham Lincoln, Ulysses S. Grant, and most Whigs) rejected it."

We are almost 100 years AFTER the War of Independence - The people who advocated and endorsed the idea of Manifest Destiny were Americans through and through, where their ancestors came from by the time we are talking about here is irrelevant.