WASHINGTON — President Trump said Tuesday that the United States needed “a good ‘shutdown’” this fall to force a partisan confrontation over federal spending and suggested that he might move to reverse longstanding Senate rules that effectively require a supermajority to approve most major pieces of legislation.

The declarations, in two posts on Twitter, appeared aimed at defending a compromise spending package that Congress is likely to clear this week, but that fails to accomplish many of Mr. Trump’s stated goals — including allocating any money to build a wall on the southern border, a project that was his most talked-about campaign promise. Conservative activists have criticized the agreement as one that does not address their priorities and swells the deficit, but the White House has signaled that the president would accept it rather than set off a government shutdown.

Senate Republicans promptly and uniformly rejected Mr. Trump’s threats of a more partisan approach in the future.

The Twitter messages were also an indication of the degree to which bipartisan negotiations in Congress on the spending bill and others, including a health care overhaul that appeared on Tuesday to be stalled again, have bedeviled Mr. Trump at this early stage of his presidency, forcing him to bow to political realities to which he had insisted he was immune.