WASHINGTON — Jeb Bush is under growing pressure to acknowledge what seems obvious to some voters and election lawyers: He is running for president.

The lawyers say Mr. Bush, a former Florida governor, is stretching the limits of election law by crisscrossing the country, hiring a political team and raising tens of millions of dollars at fund-raisers, all without declaring — except once, by mistake — that he is a candidate.

Some election experts say Mr. Bush passed the legal threshold to be considered a candidate months ago, even if he has not formally acknowledged it. Federal law makes anyone who raises or spends $5,000 in an effort to become president a candidate and thus subject to fund-raising, spending and disclosure rules. Greater latitude is allowed for those who, like Mr. Bush, say they are merely “testing the waters” for a possible run.

“When you look at the totality of the activities, could a reasonable person conclude anything other than that he is seeking the presidency?” asked Karl J. Sandstrom, a campaign finance lawyer who served on the Federal Election Commission.