After a short-lived presidential bid of his own last year, Mr. Pawlenty is again being considered for the Republican ticket. His fate is in the hands of Mr. Romney, a rival-turned-friend, who is on the cusp of announcing his vice-presidential selection. Mr. Romney has reached a decision, his friends believe, and he may disclose it as soon as this week. …

While Mr. Romney has kept more distance from the rest of his primary challengers, he has embraced Mr. Pawlenty, seeking his advice about running against President Obama and sending him to Republican events on his behalf. They began forging a closer relationship last year on a visit to the Romney family’s lakeside home in New Hampshire, aides said, and during debates this year when Mr. Pawlenty often traveled with the Romney campaign after dropping out of the race himself.

He has emerged as one of the most energetic cheerleaders and forceful defenders of Mr. Romney, firing back against Republican skeptics and Democratic critics alike. All but forgotten are the days when Mr. Pawlenty coined the troublemaking term “Obamneycare,” suggesting that few differences existed between the health care plans of Mr. Romney and Mr. Obama.